Modulation of ovarian function by various indolamines during the sexually active phase in the Indian palm squirrel, Funambulus pennanti

Abstract

We studied the effects of four indolamines (melatonin, 5-methoxytryptamine, 5-methoxytryptophol, and 5-methoxytryptophan) on ovarian activity in a tropical rodent, the Indian palm squirrel (Funambulus pennati), during the sexually active phase. Injection of the four 5-methoxyindoles at a dose of 20 μg/0.1 mL per animal every evening for 30 days reduced ovarian mass in both intact and pinealectomized animals. Intact animals treated with 5-methoxyindoles had a lower uterine mass than the intact controls. On the other hand, the uterine mass of pinealectomized animals treated with 5-methoxyindoles did not differ from that of their respective controls. Plasma estradiol levels showed a similar pattern to ovarian masses. We conclude that the effect of 5-methoxyindoles in the female palm squirrel is independent of the pineal gland and that 5-methoxytraptophol and 5-methoxytryptophan are more potent than melatonin.