Melatonin concentration before and during testosterone replacement in primary hypogonadic men

Abstract

Objective: To study circadian levels of melatonin in primary hypogonadic adult men before and after testosterone treatment. Design and methods: Circadian serum melatonin profiles were studied in six men with primary hypogonadism before and during testosterone substitution and compared with an age-matched control group (n ¼ 6). Results: Hypogonadal patients had higher plasma melatonin concentrations than the control group during day time (34:2 Ϯ 8:8 compared with 5:4Ϯ 0:5 ng/l, means Ϯ S.D.; P < 0:005) and night-time (74:8 Ϯ 34:5 compared with 30:8 Ϯ 3:2 ng/l). A 3 months course of testosterone replacement treatment in the hypogonadal group was followed by a diminution of the amplified melatonin circadian rhythm, with lower mean values both during the day (34:2:8 Ϯ 8 compared with 12:7 Ϯ 2:45 ng/l, P <0:001) and at night (74:8 Ϯ 34:5 compared with 41:5 Ϯ 13:5 ng/l, P <0:01), and a decrease in the total area under the curve (958 Ϯ 318 compared with 475:5 Ϯ 222:9, P ¼ 0:046). There was a significant negative correlation between melatonin (r ¼ ¹0:69) and testosterone concentrations. Conclusions: These data indicate that diminished testosterone in male primary hypogonadism is associated with enhanced plasma levels of melatonin, and that testosterone substitution treatment induces a deamplification of the circadian rhythm of melatonin values in humans.

Melatonin as a Biomarker of Circadian Dysregulation

“…Human studies indicate that decreased concentrations of circulating melatonin (such as those brought about by circadian disruption) can result in increased release of the gonadotropins luteinizing hormone and follicle-stimulating hormone from the pituitary and estrogen release by the ovaries (21)(22)(23)(24)(25). There is also evidence from clinical studies of a relationship between melatonin and male reproductive hormones (26)(27)(28)(29). Thus, through its control over gonadal hormone production, melatonin may have an inhibitory effect on hormone-dependent tumors.…”

Altered melatonin secretion in hypogonadal men: clinical evidence

“…(1988), Ozata et al. (1996) and Rajmil et al. (1997), who found increased melatonin secretion in patients with hypergonadotropic hypogonadism.…”

“…The data of serum melatonin levels in primary hypogonadism are controversial and more studies are needed to clarify this issue. Luboshitzky et al (1996Luboshitzky et al ( , 1997 found low melatonin levels in primary hypogonadism, whereas Tortosa et al (1988) and Rajmil et al (1997) reported increased serum melatonin levels in primary hypogonadism.…”

“…(1996, 1997) found low melatonin levels in primary hypogonadism, whereas Tortosa et al. (1988) and Rajmil et al. (1997) reported increased serum melatonin levels in primary hypogonadism.…”

Prolonged weakening of the geomagnetic field (GMF) affects the immune system of rats

“…Okatani et al [1999] showed that the increase in melatonin synthesis in a perimenopausal period in female rats might originate in the decreased levels of an endogenous estrogen. The effect of male sex hormones on melatonin level has not been thoroughly understood; however, it has been shown that under some pathological conditions the deficit of male hormones leads to an abnormal increase in melatonin level, while treatment with testosterone normalizes them [Luboshitzky et al, 1996;Rajmil et al, 1997]. It has been suggested that testosterone affects melatonin level by modulating its metabolism [Caglayan et al, 2001].…”