EFFECTS OF LEUPROLIDE-INDUCED HYPOGONADISM AND TESTOSTERONE REPLACEMENT ON SLEEP, MELATONIN, AND PROLACTIN SECRETION IN MEN

The possible role of gonadal steroids in regulating sleep and circadia n rhythms in humans has received relatively little attention despite t he importance of the topic to several clinical syndromes. Pharmacologi cally induced hypogonadism, with and without gonadal steroid replaceme nt, provides an opportunity to examine these questions within a contro lled experimental design. We used leuprolide acetate, with and without testosterone replacement, to study the role of testosterone in the re gulation of sleep and of melatonin, PRL, and TSH secretion in men. Res ults from 10 men revealed significant decreases in 24-h PRL levels and in the percentage and time of stage 4 sleep in the hypogonadal state compared with testosterone replacement. There were no differences in m elatonin or TSH secretion or in the timing or duration of sleep betwee n the two hormonal conditions. These results indicate that testosteron e has relatively specific and discrete effects on sleep and hormonal r hythms in men.