Effect of melatonin alone or in combination with human chorionic gonadotropin or ovine luteinizing hormone on the in vitro secretion of estrogens or progesterone by granulosa cells of rats.

Abstract

This work was undertaken to learn what effect, if any, melatonin might have on estrogen and progesterone production in vitro. Granulosa cells (10(6)/tube) were harvested from immature Sprague-Dawley rats, previously primed with diethylstilbestrol. Such cells were incubated for 90 min in medium only or in medium to which hCG (10 or 100 IU) or melatonin (3, 30, or 300 pg) had been added separately and in combination. Melatonin alone had no significant effect on the amount of estrogen produced, but in combination with hCG, a significant increase in estrogen followed (P less than 0.05). Estrogen was measured by RIA. More mature granulosa cells from rats primed with both diethylstilbestrol and porcine FSH were similarly collected and incubated in medium alone or in medium containing ovine LH (oLH; 0.3 or 3 ng) and/or melatonin (23 or 23 X 10(2) pg). The progesterone produced was measured by a competitive protein-binding method. A significant increase (P less than 0.05) in progesterone followed the addition of either melatonin or oLH alone, but a substantially greater increase was seen when oLH and melatonin were combined. These results show that, at least over a short period (90 min), melatonin is progonadal, in that it augments gonadotropic stimulation of granulosa cells and leads to increased synthesis of estrogen or progesterone. Melatonin may also independently stimulate granulosa cell production of progesterone.