Effect of gonadotropic hormones on the rat pineal gland A fluorescence histochemical and biochemical study

Changes in the number of autofluorescent and serotonin-containing pinealocytes have been studied after gonadotropic hormone administration using fluorescence histochemistry. Moreover, the 5-HT levels in the pineal gland were determined biochemically under the same experimental conditions. The results suggests that pineal 5-HT levels are not influenced by increased gonadotropin levels, while the amount of autofluorescent pinealocytes increases after gonadotropin injections. It has been postulated that differences in androgenic hormone levels could not cause the changes in the number of autofluorescent pinealocytes. The reaction of the pineal gland to increased gonadotropin levels seemed important in view of the regulatory function of the epiphysis on the hypothalamo-hypophyseo-gonadal axis.