Knowledge Tree
Relations (1)
related 5.46 — strongly supporting 43 facts
Testosterone and luteinizing hormone (LH) are physiologically linked, as LH stimulates Leydig cells in the testes to produce testosterone from cholesterol [1][2], with testosterone exerting negative feedback on LH secretion [3]. They exhibit shared seasonal fluctuations in adult males, with non-synchronous annual peaks [4][5], direct correlations in serum levels [6], and frequent co-measurement in studies [7][8].
Facts (43)
Sources
Seasonal Changes of Serum Gonadotropins and Testosterone in ... frontiersin.org 33 facts
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).
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.
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.
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.
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.
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.
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.
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.
measurementMeriggiola et al. (35) studied 16 healthy men in Italy and found annual peaks for testosterone, LH, and FSH in summer.
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.
Physiology, Male Reproductive System - StatPearls - NCBI Bookshelf ncbi.nlm.nih.gov 6 facts
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.
claimLH stimulates Leydig cells in the interstitium of the testes to produce testosterone from cholesterol.
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).
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.
Cycle Syncing Through Your Menstrual Phases trinityhealthmichigan.org 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.
The Normal Menstrual Cycle and the Control of Ovulation - NCBI - NIH ncbi.nlm.nih.gov 1 fact
claimLuteinizing hormone (LH) stimulates the production of androstenedione and, to a lesser degree, testosterone in theca cells.
Understanding Male Hormonal Changes: A Complete Guide (2025) coremedicalwellness.com 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.
10.7: Homeostasis and Feedback - Biology LibreTexts bio.libretexts.org 1 fact
claimThe regulation of testosterone (T) levels in the body involves a negative feedback loop where the hypothalamus releases gonadotropin-releasing hormone (GnRH), which triggers the pituitary gland to release luteinizing hormone (LH), which then stimulates the gonads to produce testosterone; when testosterone levels in the bloodstream are too high, the testosterone feeds back on the hypothalamus to inhibit the production of GnRH.