Abnormal melatonin secretion in male patients with hypogonadism

Abstract

Recently we have demonstrated that melatonin secretion is increased in untreated male patients with GnRH deficiency. Testosterone administration to these patients decreased melatonin secretion to normal levels. These data, however, did not exclude a gonadotropic effect on melatonin secretion. To further elucidate whether gonadal steroids and/or gonadotropins modulate melatonin secretion in humans we compared untreated young males with hypogonadotropic hypogonadism (IGD, n = 6), and hypergonadotropic hypogonadism caused by KlinEfelter's syndrome (KS, n = 11) to normal pubertal male controls (n = 7). KS patients were subdivided into two groups: KS-1, with low testosterone; and KS-2, with normal testosterone levels. Serum samples for melatonin concentrations were obtained every 15 min from 7 PM to 7 AM in a controlled light-dark environment with simultaneous sleep recordings. All KS patients had elevated gonadotropin levels and decreased melatonin levels. Mean (+/- SD) dark-time nocturnal melatonin levels in KS-1 were 92 +/- 21 pmol/L and were 146 +/- 46 pmol/L in KS-2 compared with 178 +/- 64 pmol/L in controls. Integrated nocturnal melatonin secretion values (AUC) were 64 +/- 14 pmol/min x L x 10(3) in KS-1 and 96 +/- 29 pmol/min x L x 10(3) in KS-2 compared with 116 +/- 42 pmol/min x L x 10(3) in controls. All IGD patients had low gonadotropin and testosterone levels. Their dark-time melatonin levels (286 +/- 26 pmol/L) and the AUC values (184 +/- 15 pmol/min/L x 10(3)) were increased. These data indicate that melatonin secretion is increased in male patients with GnRH deficiency and decreased in low testosterone hypergonadotropic hypogonadal patients. Taken together, our results suggest that both gonadotropins and gonadal steroids modulate melatonin secretion in humans.

Neurohypophysial hormone and melatonin secretion over the natural and suppressed menstrual cycle in premenopausal women

“…Melatonin levels have been shown to be increased in women with hypothalamic and secondary amenorrheoa (Brzezinski et al, 1988;Berga et al, 1988;Laughlin et al, 1991;Okatani & Sagara, 1994;Hoffmann et al, 1996). Melatonin levels have also been found to be increased in hypogonadal men (Luboshitzky et al, 1996) and gonadal steroid receptors have been found in the human pineal (Luboshitzky et al, 1997). Exogenous melatonin enhances luteinizing hormone levels (Cagnacci et al, 1995b) and its response and that of follicle-stimulating hormone to gonadotropin-releasing hormone in the follicular, but not in the luteal phase of the menstrual cycle (Cagnacci et al, 1995a).…”

Melatonin profiles and sleep characteristics in boys with fragile X syndrome: A preliminary study

“…This has led to the suggestion that a rapid decrease in endogenous melatonin at pubertal onset facilitates the maturation of the neuro-endocrine reproductive axis [Puig-Domingo et al, 1992;Waldhauser et al, 1984]. Luboshitzky et al [1996] claim that melatonin is inversely related to sex steroid production, such that pineal tumors have been associated with precocious puberty [Wirz-Justice and Armstrong, 1996;Wurtman et al, 1963].…”

Melatonin profiles and sleep characteristics in boys with fragile X syndrome: A preliminary study

“…This has led to the suggestion that a rapid decrease in endogenous melatonin at pubertal onset facilitates the maturation of the neuro‐endocrine reproductive axis [Puig‐Domingo et al, 1992; Waldhauser et al, 1984]. Luboshitzky et al [1996] claim that melatonin is inversely related to sex steroid production, such that pineal tumors have been associated with precocious puberty [Wirz‐Justice and Armstrong, 1996; Wurtman et al, 1963].…”