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luteinizing hormone (LH)
Also known as: LH, luteinizing hormone (LH), luteinizing hormone
synthesized from dimensionsLuteinizing hormone (LH) is a vital glycoprotein gonadotropin secreted by the anterior pituitary gland. It serves as a fundamental component of the hypothalamic-pituitary-gonadal axis, with its production and release governed by the pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus, a process further modulated by factors such as kisspeptin and circadian rhythms pituitary LH during sleep. Structurally, LH belongs to the same glycoprotein family as follicle-stimulating hormone (FSH), sharing an identical alpha subunit while possessing a unique beta-subunit that confers its specific biological activity.
In females, LH is essential for the regulation of the menstrual cycle LH in menstrual cycle. During the follicular phase, rising estrogen levels trigger a characteristic LH surge, which typically occurs 34 to 50 hours before ovulation. This surge is the primary physiological trigger for the resumption of oocyte meiosis, the luteinization of granulosa cells, and the final release of a mature egg from the dominant follicle. Following ovulation, LH is required to maintain the corpus luteum, which secretes progesterone and estradiol to prepare the endometrium for potential implantation. Because of its distinct surge, LH is the target hormone detected by home ovulation test kits.
In males, LH acts primarily on the Leydig cells within the testes. Through a G protein-coupled receptor mechanism that increases intracellular cAMP, LH stimulates the activity of desmolase, the rate-limiting enzyme that converts cholesterol into pregnenolone, thereby facilitating testosterone production. This testosterone secretion is critical for sexual development, function, and the continuation of spermatogenesis pituitary LH for spermatogenesis. Testosterone subsequently exerts negative feedback on the hypothalamus and pituitary to regulate further LH secretion.
Clinical assessment of LH is a standard component of reproductive health panels LH in blood tests, often measured alongside testosterone and FSH LH in male hormone tests. The standard laboratory reference range for LH is generally 1–9 IU/L LH reference range 1-9 IU/L, typically measured via Chemiluminescent Microparticle Immunoassay LH immunoassay method. Clinically, elevated LH levels in the presence of low testosterone are diagnostic of primary (hypergonadotropic) hypogonadism, while congenital LH deficiency is a known cause of secondary hypogonadism, such as in Kallmann’s syndrome LH deficiency causes hypogonadism.
Regarding potential seasonal or circannual fluctuations in LH levels, scientific consensus remains elusive. While some studies have reported seasonal peaks in men—such as autumn peaks in French cohorts Reinberg autumn LH peak or winter peaks in pre-pubertal boys Bellastella winter LH peak—other research conducted in extreme environments like Antarctica has found no evidence of seasonality no LH seasonality Antarctica. Furthermore, evidence suggests that LH exhibits less annual variability than testosterone testosterone more variable than LH and is not significantly influenced by daylight exposure no daylight LH influence. There is no established correlation between LH and prolactin levels in males no PRL-LH correlation.
Model Perspectives (4)
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Luteinizing hormone (LH) is a critical hormone produced by the anterior pituitary gland [4, 13, 52] that plays a central role in both female and male reproductive physiology. Its regulation is governed by the hypothalamus via gonadotropin-releasing hormone (GnRH) [13, 17].
In females, LH is essential for the menstrual cycle [12, 55]. During the follicular phase, rising levels of estrogen—specifically when reaching concentrations above 200 pg/mL for approximately 50 hours—trigger a surge of LH [8, 31, 53]. This surge causes final egg maturation and the release of the egg from the follicle [8, 21, 36]. Following ovulation, LH remains necessary to support the corpus luteum [42, 57], which produces progesterone to prepare the uterine lining for potential implantation [1, 56]. The secretion of both progesterone and estradiol during the luteal phase is episodic and correlates with LH pulses [45].
In males, LH modulates hormone production in the testes [4] by stimulating Leydig cells through a G protein-coupled receptor mechanism that increases cellular cAMP levels [51]. LH promotes the activity of desmolase, the rate-limiting enzyme that converts cholesterol into pregnenolone, facilitating the production of androgen intermediates [60]. Clinical assessment of male hormonal issues often involves measuring LH alongside testosterone and FSH [9, 15].
Research indicates that LH levels in males exhibit circannual (seasonal) fluctuations, with consistent evidence of higher levels occurring in the spring and autumn [2, 6, 23, 54]. While testosterone also fluctuates seasonally, these variations are not necessarily synchronous with LH, suggesting potentially distinct regulatory mechanisms [58, 59]. For example, the testosterone zenith may occur months after the spring LH peak [48]. Some evidence suggests a direct relationship between serum testosterone and LH levels [16], though this is not universal across all study populations [25].
openrouter/google/gemini-3.1-flash-lite-preview definitive 100% confidence
Luteinizing hormone (LH) is a critical gonadotropic hormone regulated by the hypothalamus and secreted by the anterior pituitary [9, 31, 43]. It plays distinct, vital roles in both male and female reproductive physiology.
In females, LH is central to the menstrual cycle [8, 14]. During the follicular phase, rising estrogen levels eventually trigger an LH surge [29, 41]. This surge is fundamental to the reproductive process; it stimulates the resumption of oocyte meiosis [10, 49], promotes the luteinization of granulosa cells [5], and ultimately triggers the release of a mature egg from the follicle [26, 33, 41]. Following ovulation, LH supports the corpus luteum [4, 22], which secretes progesterone and estradiol [20]. The maintenance of the corpus luteum is sensitive to LH pulse frequency and amplitude, and its function can be extended or diminished based on LH availability [13, 50]. Because of its role in triggering ovulation, LH is the target hormone detected by home ovulation test strips [55].
In males, LH acts on Leydig cells within the testes to stimulate the production of testosterone from cholesterol [1, 35]. The hypothalamus maintains systemic LH levels through the pulsatile release of GnRH [11]. Research on seasonal patterns has yielded mixed results: while some studies suggest biannual or circannual fluctuations in LH levels in men [12, 18, 37, 47], other research has found no such seasonality [30, 46]. Furthermore, while some data indicates a direct relationship between LH and testosterone [12, 38, 56], other findings suggest that observed seasonal variations in testosterone may be independent of LH, potentially reflecting a higher sensitivity to environmental factors like temperature or daylight [60]. Clinically, high levels of LH in the presence of inadequate testosterone production or impaired spermatogenesis are diagnostic of primary, or hypergonadotropic, hypogonadism [17].
openrouter/google/gemini-3.1-flash-lite-preview definitive 100% confidence
Luteinizing hormone (LH) is a glycoprotein hormone produced by the pituitary gland [20] that plays a critical role in the reproductive systems of both males and females. Structurally, LH and follicle-stimulating hormone (FSH) belong to the same glycoprotein family, sharing identical alpha subunits but possessing unique beta-subunits [15]. Its secretion is governed by the hypothalamic-pituitary-gonadal axis [42], specifically through the pulsatile release of gonadotropin-releasing hormone (GnRH) from the hypothalamus, a process regulated by Kisspeptin and hypothalamic clock genes [11, 46].
In females, LH is essential for the menstrual cycle [24, 30]. During the follicular phase, LH and FSH stimulate the growth of follicles within the ovaries [39]. As estrogen levels reach a peak, they trigger a significant surge of LH [1, 5], which occurs approximately 34 to 36 hours before ovulation [28]. This surge is the primary trigger for the release of an egg from the dominant follicle into the fallopian tube [40, 47]. Furthermore, the LH surge stimulates the luteinization of granulosa cells and the synthesis of progesterone [7, 16], aiding in the regulation of the subsequent luteal phase [22, 44]. During menopause, LH levels increase as ovarian hormone production declines [31].
In males, LH acts on Leydig cells to stimulate testosterone production [43], which supports sexual development and function [42]. Testosterone, in turn, exerts negative feedback on the hypothalamus and anterior pituitary to regulate the secretion of LH and FSH [41]. While some research suggests potential circannual rhythms in LH levels in men [12, 17, 25], findings are inconsistent [8, 26], and it is hypothesized that ancestral seasonal secretory patterns may be diminishing in humans due to industrialized environments [36]. Research indicates that LH levels in males may be related to minimum temperatures [13] and that elevated LH levels are sometimes correlated with sexual hypofunction [35].
openrouter/x-ai/grok-4.1-fast 85% confidence
Luteinizing hormone (LH) is a hormone secreted by the pituitary gland, crucial for reproductive processes. The Cleveland Clinic states that LH, produced by the pituitary, is necessary to continue spermatogenesis pituitary LH for spermatogenesis. Washington State University reports that the pituitary secretes LH and FSH during sleep, regulating the reproductive system, with NIH associating sleep to LH secretion pituitary LH during sleep. In diagnostics, Infusion Health notes medical professionals order LH blood tests for male hormonal issues alongside testosterone and FSH LH in male hormone tests, while Core Medical Wellness includes LH in male health panels LH in blood tests. Laboratory reference range for LH is 1–9 IU/L LH reference range 1-9 IU/L, measured via Chemiluminescent Microparticle Immunoassay with low assay variation LH immunoassay method. Studies reveal seasonal LH variations: Reinberg et al. found autumn peaks in 260 French men Reinberg autumn LH peak, Bellastella et al. reported winter peaks in pre-pubertal Italian boys Bellastella winter LH peak, but Sawhney et al. detected none in Antarctic men no LH seasonality Antarctica; Frontiers research showed no daylight influence on LH no daylight LH influence and less annual variability than testosterone testosterone more variable than LH. National Library of Medicine indicates congenital LH deficiency causes secondary hypogonadism like Kallmann’s syndrome LH deficiency causes hypogonadism. In women, Preston's Pharmacy describes LH regulating the 28-day menstrual cycle with estrogen, progesterone, and FSH LH in menstrual cycle. No correlation exists between LH and prolactin in males no PRL-LH correlation.
Facts (170)
Sources
Seasonal Changes of Serum Gonadotropins and Testosterone in ... frontiersin.org Jan 9, 2020 50 facts
measurementLuteinizing hormone (LH) seasonality was confirmed for data within the laboratory reference range (1–9 IU/L), with higher levels confirmed in spring and autumn (p = 0.001).
claimLuteinizing hormone (LH) in adult human males shows a bi-annual fluctuation with two peaks reached in spring and autumn.
measurementReinberg et al. (38) studied 260 men undergoing vasectomy in France (median age 32 years) and found annual peaks for testosterone and LH in autumn, and an annual peak for FSH in summer.
procedureInclusion criteria for the study required male patients to be older than 18 years and to have testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) measured in the same venous blood sample taken in the morning after an overnight fast.
measurementTotal serum testosterone levels are directly related to luteinizing hormone (LH) (R = 0.147, p < 0.001), but not to follicle-stimulating hormone (FSH) (R = -0.006, p = 0.482).
referenceNicolau et al. (1985) investigated circadian and circannual variations of FSH, LH, testosterone, DHEA-S, and 17-hydroxy progesterone in elderly men and women.
measurementIn the third group of patients studied, seasonal differences for both testosterone and luteinizing hormone (LH) were confirmed (p = 0.004 and p = 0.002, respectively), with the highest testosterone levels detected in summer (p = 0.002) and the highest LH levels in spring and autumn (p = 0.004 and p = 0.006, respectively).
measurementLuteinizing hormone (LH) serum levels in males were significantly higher in spring compared to summer (p = 0.004) and winter (p < 0.001), and in autumn compared to winter (p = 0.044) and summer (p < 0.001).
measurementSawhney et al. (39) studied 9 healthy men in Antarctica and found bi-annual peaks for testosterone in summer and autumn, with no seasonality detected for LH or FSH.
measurementThe laboratory reference ranges used in the study were 2.2–8.7 ng/dL for testosterone, 1–9 IU/L for LH, 1–12 IU/L for FSH, and 3–13 ng/mL for PRL.
claimThe circannual fluctuations of testosterone and luteinizing hormone (LH) in males are possibly regulated by different mechanisms, with central regulation for LH and environmental regulation for testosterone.
procedureTo evaluate the role of age on sexual hormone variations, the researchers divided the entire cohort into quartiles based on age distribution and evaluated testosterone, LH, and FSH distribution among seasons within each quartile.
measurementSerum luteinizing hormone (LH) levels in the study cohort had a mean of 4.64 ± 2.54 IU/L, with a range of 1.00–15.00 IU/L.
measurementIn the fourth group of patients studied, no seasonal differences were detected for either testosterone (p = 0.155) or luteinizing hormone (LH) (p = 0.080).
procedureThe study 'Seasonal Changes of Serum Gonadotropins and Testosterone in...' analyzed testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) measurements collected between January 2010 and January 2019 using Chemiluminescent Microparticle Immunoassay, excluding subjects with factors interfering with the hypothalamic-pituitary-gonadal axis.
claimProlactin (PRL) serum levels in adult human males do not correlate with testosterone (Rho: 0.002, p = 0.804), luteinizing hormone (Rho: 0.005, p = 0.665), or follicle-stimulating hormone (Rho: 0.006, p = 0.734).
claimThe testosterone zenith in males is reached at least 3 months after the luteinizing hormone (LH) peak, which may be a late consequence of the vernal LH peak.
measurementIn a study of adult human males, serum luteinizing hormone (LH) levels showed a statistically significant seasonal variation (p = 0.001), with mean levels of 4.30 IU/L in winter, 4.46 IU/L in spring, 4.22 IU/L in summer, and 4.45 IU/L in autumn.
claimLuteinizing hormone (LH) serum levels in males exhibit a seasonal distribution with two annual peaks occurring in spring and autumn.
claimAdult human males exhibit a clear seasonal fluctuation of both luteinizing hormone (LH) and testosterone, though the annual fluctuation of these two hormones is not synchronous.
measurementIn a study of seasonal hormonal variations, serum luteinizing hormone (LH) levels in males were measured as 4.56 IU/L in winter, 4.78 IU/L in spring, 4.44 IU/L in summer, and 4.72 IU/L in autumn, with a p-value of <0.001.
procedureTo evaluate the role of the environment on sexual hormones, the researchers performed bivariate correlations between testosterone, LH, and FSH and environmental factors including maximum, minimum, and mean temperatures, humidity, and daylight duration using Rho's Spearman correlation.
claimThe study on seasonal changes of serum gonadotropins and testosterone in males concluded that there are biannual or circannual fluctuations of serum luteinizing hormone (LH) and testosterone, which suggests a seasonal influence on the pituitary-gonadal axis in humans.
procedureThe researchers compared the mean values of testosterone, LH, and FSH among seasons using the Kruskal-Wallis test, followed by post hoc analyses using the Tukey test.
claimSerum luteinizing hormone (LH) levels in men present two peaks of secretion in autumn and spring, independently of environmental parameters.
claimThe annual change in testosterone in adult human males shows wider variability in annual values compared to luteinizing hormone (LH), with testosterone levels fluctuating both below and above laboratory reference ranges, while luteinizing hormone fluctuations remain irrespective of the reference range.
referenceMeriggiola et al. (1996) examined annual patterns of luteinizing hormone, follicle-stimulating hormone, testosterone, and inhibin in normal men.
measurementAbbaticchio et al. (27) studied 248 infertile men in Italy (mean age 28.9 ± 7.5 years) and detected no seasonality for testosterone, LH, or FSH.
measurementSerum luteinizing hormone (LH) is directly related to follicle-stimulating hormone (FSH) (R = 0.538, p < 0.001).
measurementIn the second group of patients studied, serum luteinizing hormone (LH) levels differed significantly among seasons (p < 0.001), with the highest levels occurring in spring and autumn (p < 0.001 and p = 0.005, respectively), though an annual peak for testosterone was not confirmed (p = 0.060).
measurementPatient age is inversely related to serum testosterone levels (R = -0.148, p < 0.001) and directly related to luteinizing hormone (LH) (R = 0.185, p < 0.001) and follicle-stimulating hormone (FSH) (R = 0.281, p < 0.001).
procedureThe researchers evaluated the distribution of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) based on the date of examination using autocorrelation analyses.
measurementBellastella et al. (28) studied 106 pre-pubertal males in Italy (age range 6–10 years) and found an annual peak for testosterone in summer and an annual peak for LH in winter, with no seasonality detected for FSH.
measurementMartikainen et al. (34) studied 22 young men in Finland and detected no seasonality for testosterone, LH, or FSH.
claimAutocorrelation function analysis of luteinizing hormone (LH) distribution in males identified two significant peaks (peak 1: 0.216, p < 0.001; peak 2: 0.108, p < 0.001), which was confirmed by the Wilcoxon Signed Rank test (p = 0.001).
measurementTestosterone, LH, and FSH levels in the study cohort were not normally distributed (p < 0.001).
measurementNicolau et al. (36) studied 63 healthy men in Romania (mean age 77.0 ± 8.0 years) and found annual peaks for testosterone and LH, but no seasonality for FSH.
claimIn the study, the authors found no influence of daylight duration on luteinizing hormone (LH) secretion, suggesting a mechanism independent from melatonin.
claimTestosterone seasonality in men is independent of luteinizing hormone (LH) fluctuations, suggesting testosterone may be more sensitive to environmental temperatures and daylight duration.
measurementLuteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured using Chemiluminescent Microparticle Immunoassay (Architect, Abbott, Longford, Ireland). The inter- and intra-assay coefficients of variation were 4.1% and 3.1% for LH, and 4.6% and 4.2% for FSH, respectively.
claimLuteinizing hormone (LH) serum levels in males did not show any significant trend across the years of the study.
claimLuteinizing hormone (LH) secretion is the result of gonadotropin-releasing hormone (GnRH) pulsatility, which is regulated by hypothalamic clock genes and the pulsatile secretion of Kisspeptin.
measurementMeriggiola et al. (35) studied 16 healthy men in Italy and found annual peaks for testosterone, LH, and FSH in summer.
claimLuteinizing hormone (LH) in adult human males is directly related to minimum temperatures, but not to maximum or mean temperatures, humidity, or daylight duration.
measurementBellastella et al. (29) studied 10 healthy men in Italy (age range 25–30 years) and found an annual peak for testosterone in autumn and an annual peak for LH in spring, with no seasonality detected for FSH.
claimIf the rhythmicity of testosterone and luteinizing hormone reflected a direct connection between the pituitary gland and the testicle, there would be two testosterone peaks every year.
referencePrepubertal males exhibit circannual rhythms of plasma luteinizing hormone, follicle-stimulating hormone, testosterone, prolactin, and cortisol, according to a 1983 study by Bellastella et al.
measurementIn the first group of patients studied, serum luteinizing hormone (LH) and testosterone levels did not differ significantly among seasons (p = 0.773 and p = 0.301, respectively).
claimThe ancestral secretory pattern of hormones adaptive to seasons in various animal species may be gradually disappearing in humans, as evidenced by the limited amplitude of testosterone and luteinizing hormone (LH) fluctuations across the year, the absence of seasonality in the youngest and oldest age groups, and reduced exposure to environmental factors in the industrialized era.
claimLuteinizing hormone (LH) seasonality appears to be independent of the environment and may be regulated by a central mechanism involving the hypothalamic gonadotropin-releasing hormone (GnRH).
The Normal Menstrual Cycle and the Control of Ovulation - NCBI - NIH ncbi.nlm.nih.gov Aug 5, 2018 47 facts
claimAdministration of Luteinizing hormone (LH) or Human Chorionic Gonadotropin (HCG) during the luteal phase can extend corpus luteum function for an additional two weeks.
claimThe postovulatory decline in luteinizing hormone (LH) may be caused by the loss of the positive feedback effect of estrogen, the increasing inhibitory feedback effect of progesterone, or the depletion of pituitary LH content due to downregulation of GnRH receptors.
claimIn most women, the Luteinizing hormone (LH) pulse amplitude begins to increase after ovulation occurs.
measurementTo produce the critical concentration of estradiol required to initiate positive feedback for the luteinizing hormone (LH) surge, the dominant follicle is almost always greater than 15mm in diameter as measured by ultrasound.
claimThe luteinizing hormone (LH) surge stimulates the resumption of meiosis and the completion of reduction division in the oocyte, resulting in the release of the first polar body.
measurementOvulation occurs approximately 10-12 hours after the luteinizing hormone (LH) peak.
claimDuring the late follicular phase prior to ovulation, the pulse frequency of Luteinizing hormone (LH) increases and the pulse amplitude may begin to increase.
claimIn response to luteinizing hormone (LH) and progesterone, prostaglandins and proteolytic enzymes (such as collagenase and plasmin) increase and digest collagen in the follicular wall, leading to the release of the oocyte-cumulus complex.
claimIn most women, the Luteinizing hormone (LH) pulse amplitude begins to increase after ovulation takes place.
claimThe luteinizing hormone (LH) surge is initiated by a dramatic rise in estradiol produced by the preovulatory follicle.
claimThe secretion of progesterone and estradiol during the luteal phase is episodic and correlates closely with pulses of Luteinizing hormone (LH) secretion.
measurementDuring the early follicular phase of the menstrual cycle, Luteinizing hormone (LH) secretion occurs at a pulse frequency of 60 to 90 minutes with relatively constant pulse amplitude.
measurementFor the positive feedback effect of Luteinizing hormone (LH) release to occur, estradiol levels must be greater than 200 pg/mL for approximately 50 hours.
claimThe life span of the corpus luteum depends on continued luteinizing hormone (LH) support.
claimThe corpus luteum's life span depends on continued luteinizing hormone (LH) support, and its function declines by the end of the luteal phase unless human chorionic gonadotropin is produced by a pregnancy.
claimThe luteinizing hormone (LH) surge stimulates the luteinization of granulosa cells and the synthesis of progesterone, which is responsible for the midcycle follicle-stimulating hormone (FSH) surge.
measurementDuring the early follicular phase of the menstrual cycle, Luteinizing hormone (LH) secretion occurs at a pulse frequency of 60 to 90 minutes with a relatively constant pulse amplitude.
claimThe luteinizing hormone (LH) surge stimulates the resumption of meiosis and the completion of reduction division in the oocyte, resulting in the release of the first polar body.
claimThe life span of the corpus luteum can be reduced by continuous Luteinizing hormone (LH) administration during the follicular or luteal phase, reduced LH concentration, decreased LH pulse frequency, or decreased LH pulse amplitude.
claimLuteinizing hormone (LH) stimulates the production of androstenedione and, to a lesser degree, testosterone in theca cells.
claimThe frequency and amplitude of LH secretion during the follicular phase regulates subsequent luteal phase function.
claimThe secretion of progesterone and estradiol during the luteal phase is episodic and correlates closely with pulses of LH secretion.
claimIn the presence of estradiol, follicle-stimulating hormone (FSH) stimulates the formation of luteinizing hormone (LH) receptors on granulosa cells, allowing for the secretion of small quantities of progesterone and 17-hydroxyprogesterone (17-OHP), which may exert a positive feedback on the estrogen-primed pituitary to augment LH release.
claimLuteinizing hormone (LH) was established as the primary luteotropic agent in a cohort of hypophysectomized women.
measurementFor the positive feedback effect of Luteinizing hormone (LH) release to occur, estradiol levels must exceed 200 pg/mL for approximately 50 hours.
referenceA 1978 study published in the American Journal of Obstetrics and Gynecology examined the temporal relationships of estrogen, progesterone, and luteinizing hormone levels to ovulation in women and infrahuman primates.
claimLuteinizing hormone (LH) levels are low during the early follicular phase of the menstrual cycle and begin to rise by the mid-follicular phase due to positive feedback from rising estrogen levels.
claimAndrogens, glucocorticoids, and pituitary hormones (excluding LH and FSH) exhibit only minimal fluctuation during the normal menstrual cycle.
claimAdministration of LH or HCG during the luteal phase can extend corpus luteum function for an additional two weeks.
claimThe luteinizing hormone (LH) surge stimulates the resumption of meiosis and the completion of reduction division in the oocyte, resulting in the release of the first polar body.
claimThe life span of the corpus luteum can be reduced by continuous LH administration, reduced LH concentration, decreased LH pulse frequency, or decreased LH pulse amplitude.
measurementOvulation occurs approximately 10-12 hours after the luteinizing hormone (LH) peak.
referenceErickson G.F., Wang C., and Hsueh A.J. published a study in 1979 in the journal Nature titled 'FSH induction of functional LH receptors in granulosa cells cultured in a chemically defined medium', which details the induction of luteinizing hormone receptors by follicle-stimulating hormone.
claimSpontaneous luteinization of granulosa cells can occur in the absence of luteinizing hormone (LH), suggesting that inhibitory factors like oocyte maturation inhibitor or luteinization inhibitor are overcome at ovulation.
claimDuring the late follicular phase prior to ovulation, the pulse frequency of Luteinizing hormone (LH) secretion increases and the amplitude may begin to increase.
claimElevated follicle-stimulating hormone (FSH) levels at midcycle are thought to free the oocyte from follicular attachments, stimulate plasminogen activator, and increase granulosa cell luteinizing hormone (LH) receptors.
referenceThe two-cell, two-gonadotropin hypothesis of regulation of estrogen synthesis in the human ovary states that LH stimulates theca cells to produce androstenedione, which is then transported to granulosa cells where it is aromatized to estrone and converted to estradiol by 17-β-hydroxysteroid dehydrogenase type I.
claimThe luteinizing hormone (LH) surge stimulates the luteinization of granulosa cells and the synthesis of progesterone, which is responsible for the midcycle follicle-stimulating hormone (FSH) surge.
claimSpontaneous luteinization of granulosa cells can occur in the absence of luteinizing hormone (LH), leading to the hypothesis that inhibitory factors like oocyte maturation inhibitor or luteinization inhibitor are overcome at ovulation.
claimThe frequency and amplitude of Luteinizing hormone (LH) secretion during the follicular phase regulates subsequent luteal phase function.
claimLuteinizing hormone may contribute to the termination of the luteal phase by downregulating its own receptor.
measurementThe beginning of the luteinizing hormone (LH) surge occurs roughly 34 to 36 hours prior to ovulation.
claimProstaglandins and proteolytic enzymes, such as collagenase and plasmin, increase in response to luteinizing hormone (LH) and progesterone, leading to the digestion of collagen in the follicular wall and the release of the oocyte-cumulus complex.
claimLuteinizing hormone (LH) receptors are located on theca cells during all stages of the menstrual cycle.
referenceSherman B.M., West J.H., and Korenman S.G. published a 1976 study in the Journal of Clinical Endocrinology and Metabolism analyzing LH, FSH, estradiol, and progesterone concentrations during the menstrual cycles of older women.
claimEstradiol levels fall dramatically immediately prior to the luteinizing hormone (LH) peak, potentially due to LH downregulation of its own receptor or direct inhibition of estradiol synthesis by progesterone.
claimAfter ovulation, the amount of progesterone secreted and the length of the luteal phase are dependent on repeated Luteinizing hormone (LH) injections.
Physiology, Male Reproductive System - StatPearls - NCBI Bookshelf ncbi.nlm.nih.gov 15 facts
claimGonadotropin-releasing hormone (GnRH), produced by the hypothalamus, regulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland.
claimThe onset of male puberty is stimulated by a rise in gonadotropin-releasing hormone (GnRH) from the hypothalamus, which triggers the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary.
claimCongenital isolated GnRH, LH, or FSH deficiency can cause secondary hypogonadism, including conditions such as Kallmann’s syndrome, Prader-Willi syndrome, Lawrence-Moon syndrome, GnRH receptor mutations, beta-subunit mutations in LH or FSH, or kisspeptin/G protein-coupled receptor fifty-four mutations.
claimSecondary hypogonadism in human males results from a disruption in the hypothalamic-pituitary axis where low gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), or follicle-stimulating hormone (FSH) leads to low testosterone and impaired spermatogenesis.
claimFSH and LH exert their physiological effects by binding to and activating a G protein receptor, which activates adenylyl cyclase and increases cellular cAMP levels to stimulate Sertoli and Leydig cells.
claimLH promotes the activity of desmolase, the initial rate-limiting enzyme that converts cholesterol into pregnenolone, which is then converted into the weak androgen intermediates dehydroepiandrosterone (DHEA) and androstenedione.
claimLH stimulates Leydig cells in the interstitium of the testes to produce testosterone from cholesterol.
claimAfter the onset of puberty, the hypothalamus releases GnRH in a pulsatile fashion every one to two hours to maintain levels of FSH, LH, and plasma testosterone.
claimPrimary hypogonadism (hypergonadotropic hypogonadism) is caused by gonadal failure to produce adequate testosterone or perform spermatogenesis despite high levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
claimGnRH stimulates the anterior pituitary by binding to and activating a G protein receptor on gonadotrophs, which triggers inositol 1,4,5-triphosphate (IP3) activation and increases intracellular calcium, leading to the release of FSH (follicle-stimulating hormone) and LH (luteinizing hormone).
claimThe anterior pituitary secretes LH and FSH into the blood, which act on membrane receptors in the Leydig and Sertoli cells of the testes, respectively.
claimFSH and LH belong to the same glycoprotein family and consist of identical alpha subunits, but are differentiated by their unique beta-subunits.
claimIn cases of secondary hypogonadism, Leydig and Sertoli cells remain functional and intact but cannot exert their effects due to a lack of proper stimuli (GnRH, LH, or FSH), resulting in low testosterone levels or loss of spermatogenesis.
claimTestosterone acts on the hypothalamus and anterior pituitary via negative feedback to decrease the secretion of LH and FSH.
claimLuteinizing hormone (LH) stimulates Leydig cells to increase testosterone production, which causes the growth and pigmentation of the scrotum and penis.
Unknown source 7 facts
claimThe mechanism by which the corpus luteum regulates steroid secretion is not completely understood, though it may be determined in part by LH secretory patterns, LH receptors, or variations in the levels of enzymes regulating steroid hormone production, such as 3β-HSD, CYP17, CYP19, or side chain cleavage enzyme.
claimThe pre-ovulatory fall in estradiol may be caused by luteinizing hormone (LH) downregulation of its own receptor or by direct inhibition of estradiol synthesis by progesterone.
claimEstradiol levels fall dramatically immediately prior to the luteinizing hormone (LH) peak.
claimThe menstrual cycle is regulated by the hormones GnRH, FSH, LH, estradiol, and progesterone.
claimProgesterone and 17-hydroxyprogesterone (17-OHP) secreted by granulosa cells may exert a positive feedback on the estrogen-primed pituitary to augment luteinizing hormone (LH) release.
claimDuring a normal menstrual cycle, androgens, glucocorticoids, and pituitary hormones (excluding LH and FSH) exhibit only minimal fluctuations in concentration.
claimThe mechanism causing the postovulatory fall in luteinizing hormone (LH) is unknown.
4 Phases of Menstrual Cycle: Hormone Changes Chart - Liv Hospital int.livhospital.com Mar 19, 2026 6 facts
claimThe ovulatory phase occurs during days 13-15 of the menstrual cycle, where a significant increase in luteinizing hormone (LH) triggers the release of an egg.
claimThe female menstrual cycle relies on Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), estrogen, and progesterone for regularity.
claimDisruptions in the hormones FSH, LH, estrogen, or progesterone can lead to irregular periods or fertility issues.
claimDuring the ovulatory phase, there is a significant surge in luteinizing hormone (LH), which triggers ovulation.
claimThe hypothalamus, pituitary gland, and ovaries are the biological sources of the hormones FSH, LH, estrogen, and progesterone.
claimOvulation is marked by a spike in Luteinizing Hormone (LH) and a secondary estrogen peak.
Menstrual Cycle Phases: Decoding the Stages - Perelel perelelhealth.com Oct 22, 2024 5 facts
claimDuring the ovulation phase, estrogen levels peak, triggering a spike of luteinizing hormone (LH), which causes the release of the mature egg from its follicle into the fallopian tube towards the uterus.
quote“When people are using ovulation strips to test, they are measuring the luteinizing hormone,” notes Dr. O’Connor. “That’s the hormone that is secreted by the brain that triggers the release of the egg from the follicle.”
claimWhen estrogen levels reach their peak, they trigger the release of luteinizing hormone (LH) from the brain, which causes the egg to be released from the follicle.
claimThe menstrual cycle is guided by shifts in estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
claimThe menstrual cycle is regulated by fluctuations in the hormones estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
Understanding the Menstrual Cycle: A Breakdown of Its Four Phases raleighob.com Jan 15, 2025 4 facts
claimThe menstrual cycle is regulated by the hormones follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone.
claimDuring the early follicular phase, rising estrogen levels suppress luteinizing hormone to ensure the body's preparation for ovulation is gradual.
claimFollowing ovulation, luteinizing hormone levels decrease but remain essential to support the activity of the corpus luteum.
claimJust before ovulation, the body experiences a sharp rise in luteinizing hormone (LH) and a smaller rise in estrogen, which triggers the release of a mature egg from the dominant follicle.
Understanding the Phases of the Menstrual Cycle - Clue helloclue.com 4 facts
claimEstrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) regulate the menstrual cycle by signaling the brain, ovaries, and uterus.
claimA sudden surge in luteinizing hormone (LH) triggers the release of the egg during ovulation.
claimA sudden surge in luteinizing hormone (LH) triggers the release of the egg during ovulation, and estrogen levels drop immediately after this event.
claimDuring ovulation, a sudden surge in luteinizing hormone (LH) triggers the release of an egg from the dominant follicle into the fallopian tube.
Female Sexual Response & Hormone Control | SEER Training training.seer.cancer.gov 3 facts
claimFollicle-stimulating hormone, luteinizing hormone, estrogen, and progesterone are the primary hormones that regulate the functions of the female reproductive system.
claimFollicle-stimulating hormone and luteinizing hormone affect the ovaries and uterus, initiating the monthly reproductive cycles.
claimMenopause is characterized by decreased levels of ovarian hormones and increased levels of pituitary follicle-stimulating hormone and luteinizing hormone.
The Menstrual Cycle | Patient Education - UCSF Health ucsfhealth.org 3 facts
claimA sufficiently high level of estrogen triggers a sudden release of LH, usually around day thirteen of the cycle, which results in final egg maturation and follicular collapse.
claimThe pituitary gland secretes FSH and LH before the onset of menses, which stimulates the growth of several ovarian follicles.
claimLuteinizing hormone (LH), produced by the pituitary gland, aids in egg maturation and provides the hormonal trigger to cause ovulation and the release of eggs from the ovary.
Female Reproductive System: Structure & Function my.clevelandclinic.org Nov 28, 2022 3 facts
claimFollicle-stimulating hormone (FSH) and luteinizing hormone (LH) trigger an increase in estrogen production in the ovaries.
procedureDuring the ovulatory phase, the rise in estrogen from the dominant follicle triggers a surge in luteinizing hormone (LH) production by the brain, which causes the dominant follicle to release its egg from the ovary.
procedureDuring the follicular phase of the menstrual cycle, the brain releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which travel through the blood to the ovaries to stimulate the growth of 15 to 20 eggs, each contained within a follicle.
Which hormones are present in men + women? - MITOcare mitocare.de 2 facts
claimAfter ovulation is triggered by luteinizing hormone (LH), the mature egg moves into the fallopian tube and produces progesterone, which prepares the uterine lining for the implantation of a fertilized egg.
claimThe pituitary gland in women releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to prepare the body for pregnancy during the menstrual cycle.
Physiology, Male Reproductive System - PubMed pubmed.ncbi.nlm.nih.gov May 1, 2023 2 facts
claimFollicle-stimulating hormone (FSH) and luteinizing hormone (LH) are released from the anterior pituitary gland and modulate the production of hormones in the testes.
claimThe hypothalamic-pituitary-gonadal axis, formed by GnRH, FSH, LH, and testicular hormones, promotes and maintains sexual development and function in the male.
Follicular Phase Of Menstrual Cycle - Cleveland Clinic my.clevelandclinic.org Aug 8, 2022 2 facts
claimHigh estrogen levels toward the end of the follicular phase trigger the pituitary gland to release a surge of luteinizing hormone (LH), which causes the mature egg to be released from the follicle and ovary during ovulation.
claimStarting in the late 30s, FSH levels may increase during the follicular phase while LH levels may fail to spike, potentially leading to the release of non-viable eggs.
4.2 Sleep & Why We Sleep – Introductory Psychology opentext.wsu.edu 2 facts
claimThe pituitary gland secretes follicle-stimulating hormone (FSH) and luteinizing hormone (LH) during sleep, which are important for regulating the reproductive system.
claimSleep is associated with the secretion and regulation of hormones from several endocrine glands, including melatonin, follicle stimulating hormone (FSH), luteinizing hormone (LH), and growth hormone, according to the National Institutes of Health.
Understanding the Difference Between Men & Women Hormones prestonspharmacy.com Jan 13, 2026 2 facts
claimWomen experience monthly hormonal cycles tied to the menstrual cycle, which typically lasts 28 days and is regulated by estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
claimWomen experience monthly hormonal cycles tied to the menstrual cycle, which typically lasts 28 days and is regulated by estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
Female Reproductive Endocrinology - Gynecology and Obstetrics merckmanuals.com 2 facts
claimLuteinizing hormone (LH) and follicle-stimulating hormone (FSH) promote ovulation and stimulate the ovaries to secrete the sex hormones estradiol (an estrogen) and progesterone.
claimLuteinizing hormone (LH) and follicle-stimulating hormone (FSH) promote ovulation in the female reproductive system.
Male Hormone Changes by Age & Solutions - Infusion Health infusionhealth.org Jul 21, 2025 1 fact
procedureMedical professionals typically conduct symptom assessments and order blood tests, including total testosterone, bioavailable or free testosterone, SHBG, LH, FSH, estradiol, cortisol rhythms, thyroid markers, and basic metabolic panels, to diagnose male hormonal issues.
Menstrual Cycle (Normal Menstruation): Overview & Phases my.clevelandclinic.org Dec 9, 2022 1 fact
claimOvulation occurs roughly at day 14 of a 28-day menstrual cycle, triggered by a sudden increase in luteinizing hormone (LH) which causes the ovary to release an egg.
Reproductive Hormones endocrine.org Jan 24, 2022 1 fact
claimThe pituitary gland produces, stores, and stimulates Human Chorionic Gonadotropin (HcG), Prolactin, Luteinizing Hormone (LH), and Follicle-Stimulating Hormone (FSH).
The Menstrual Cycle: How It Changes as You Age | Mount Sinai Today health.mountsinai.org Jun 30, 2022 1 fact
procedureThe menstrual cycle proceeds in five steps: (1) The pituitary gland produces FSH, which signals the ovaries to produce estrogen. (2) When estrogen reaches a specific level for a set duration, the pituitary gland produces LH. (3) LH triggers ovulation, causing the ovary to release an egg into the fallopian tube. (4) The ovary produces progesterone to prepare the uterus for pregnancy. (5) If conception does not occur, hormone levels drop, the menstrual lining stops developing, and the lining is shed as a menstrual period.
Cycle Syncing Through Your Menstrual Phases trinityhealthmichigan.org Jan 20, 2025 1 fact
claimDuring the ovulation phase (Days 15-17), estrogen, luteinizing hormone (LH), and testosterone levels peak as the ovary releases an egg, which may result in positive mood and increased energy.
Hormones & desire - American Psychological Association apa.org Mar 1, 2011 1 fact
referenceIn a 2007 study published in 'Hormones and Behavior' (Vol. 51, No. 1), 40 judges rated photos of 30 women taken during their luteinizing hormone (LH) surge (ovulation) versus their non-fertile luteal phase to determine if they were trying to look attractive.
Understanding Male Hormonal Changes: A Complete Guide (2025) coremedicalwellness.com Oct 21, 2025 1 fact
claimBlood tests for male hormonal health typically measure total and free testosterone, thyroid hormones (TSH, T3, and T4), and other hormones such as LH, FSH, prolactin, DHEA, and cortisol.
Male Reproductive System: Structure & Function - Cleveland Clinic my.clevelandclinic.org Aug 5, 2023 1 fact
claimLuteinizing hormone (LH) is produced by the pituitary gland and is necessary to continue the process of spermatogenesis.
Hormonal changes and sexual function in aging men - PubMed - NIH pubmed.ncbi.nlm.nih.gov 1 fact
measurementDecreases in free testosterone and increases in luteinizing hormone (LH) show significant but small correlations with sexual hypofunction in men.
Hormonal Control Of Reproduction - MCAT Content - Jack Westin jackwestin.com 1 fact
claimIn females, estrogens and progesterone are released from the developing follicles, distinct from the hormones GnRH, FSH, and LH.
Physiology, Menstrual Cycle - StatPearls - NCBI Bookshelf ncbi.nlm.nih.gov Sep 27, 2024 1 fact
claimGonadotropin-releasing hormone (GnRH) travels to the anterior pituitary gland, where it activates G protein–coupled receptors, signaling the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).