SEASONAL-VARIATION OF GONADOTROPINS AND GONADAL-STEROIDS RECEPTORS INTHE HUMAN PINEAL-GLAND

Recently abnormal melatonin secretion was demonstrated in hypogonadal male patients which was normalized during testosterone administration. These results suggested that both gonadal steroids and gonadotropins may modulate melatonin secretion, probably by activating specific rece ptors in the pineal gland. We used immunohistochemistry to localize lu teinizing hormone, follicle stimulating hormone, estrogen and androgen receptors in human pineal glands. Tissues were obtained at autopsy fr om 53 adult males (aged 19-94 years) over a period of 1 year. Positive staining for the four types of receptors was evident in all 53 specim ens examined. The percent of positively stained cells revealed a signi ficant seasonal variation of gonadotropin receptors with higher values in the winter than in the summer. Day-night difference was evident on ly for follicle stimulating hormone-receptors during the summer and wi nter, with higher values at night. Androgen receptors and estrogen rec eptors were present in all specimens but did not reveal day-night or s easonal variations, These data demonstrate the presence of gonadotropi n and gonadal steroid receptors in the human pineal gland. Gonadotropi n receptors exhibited seasonal variation with higher values in the win ter. (C) 1997 Elsevier Science Inc.