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3984105 
Journal Article 
Testosterone treatment alters melatonin concentrations in male patients with gonadotropin-releasing hormone deficiency 
Luboshitzky, R; Lavi, S; Thuma, I; Lavie, P 
1996 
Yes 
Journal of Clinical Endocrinology and Metabolism
ISSN: 0021-972X
EISSN: 1945-7197 
81 
2 
770-774 
English 
8636302 
WOS:A1996TU98100059 
Recently, we demonstrated that melatonin secretion is increased in untreated male patients with GnRH deficiency. As testosterone (T) can be aromatized to estradiol (E(2)), and both T and E(2) increase during T enanthate treatment, we were interested in determining whether T treatment (when T and E(2) levels were well matched with pubertal control values) has an effect on melatonin levels in these patients. We measured nocturnal serum melatonin levels during the administration of 250 mg testosterone enantale/month for 4 months in 12 male patients with idiopathic hypogonadotropic hypogonadism (IGD; n = 6) and delayed puberty (DP; n = 6). Serum samples for melatonin and LH deteminations were obtained every 15 min from 1900-0700 h in a controlled light-dark environment. The results of melatonin profiles were compared with the pretreatment values in each group and with values obtained in six normal pubertal male controls. After 4 months of testosterone treatment, all patients attained normal serum testosterone (19.5 +/- 3.7 in IGD vs. 20.8 +/- 4.1 nmol/L in DP) and E(2) levels (83 +/- 12 in IGD vs. 84 +/- 9 pmol/L in DP). Serum LH levels were suppressed in all patients during T treatment (0.12 +/- 0.1 in IGD vs. 0.12 +/- 0.2 IU/L in DP). Before T treatment, patient melatonin levels were greater than those in age-matched pubertal controls. Melatonin levels were equal in patients and controls when T and E(2) levels were well matched. Mean (+/- SD) dark-time melatonin levels decreased from 286 +/- 23 to 157 +/- 36 pmol/L in IGD and from 217 +/- 32 to 133 +/- 47 pmol/L in DP (vs. 183 +/- 64 pmol/L in controls). The integrated melatonin values decreased to normal (from 184 +/- 16 to 102 +/- 21 in IGD and from 142 +/- 19 to 90 +/- 26 pmol/min . 1 x 10(3) in DP vs. 119 +/- 61 pmol/min . L x 10(3) in controls). The intraindividual variations in melatonin levels ranged from 7.2-14.5%. These data indicate that male patients with GnRH deficiency have increased nocturnal melatonin secretion. T treatment decreased melatonin secretion to normal levels. The results suggest that in GnRH-deficient male patients, sex steroids, rather than LH, modulate pineal melatonin in a reverse fashion. 
functional hypothalamic amenorrhea; rat pineal-gland; circadian-rhythm; ovarian-function; receptors; secretion; pituitary; estrogen; invitro; Endocrinology & Metabolism