Effects of progesterone on pituitary cells of the hen (Gallus domesticus) during the ovulatory cycle for production and release of LH and FSH.

Abstract

Dispersed pituitary cells of laying White Leghorn hens 8, 14, and 18 hr before ovulation were incubated in media containing progesterone for 2, 4, and 8 hr at 41°, and the amount of LH and FSH in the cells and media was measured by homologous RIA. When the pituitary cells of 8 hr before ovulation were incubated, an increase in the cellular LH and total LH (sum of cellular and medium LH) and in the medium FSH and total FSH was observed after 4-hr incubation. When the pituitary cells of 14 hr before ovulation were incubated, no change in the amount of LH and FSH in the cells and media was observed in any of the incubations. When the pituitary cells of 18 hr before ovulation were incubated, the cellular LH and the total LH were increased following the 4-hr incubation, and the medium FSH and the total FSH were increased following the 2-hr incubation. When LH-RH was added at 4 hr of the incubation of the pituitary cells of 18 hr before ovulation, the medium LH was increased following an additional 4-hr incubation. These results suggest that one of the actions of progesterone at the pituitary level is to stimulate the production of LH (which may not always result in the release) and FSH (which may result in the release), and that the effect differs at different times during the ovulatory cycle in the hen.