Effect of Estrogen on Yolk Deposition and Atresia of Ovarian Follicles in Hypophysectomized Hens

Abstract

Estradiol-17β was injected into hypophysectomized hens immediately after, and at 8 and 16h after hypophysectomy and the incidence of yolk deposition in the largest (F1), the second largest (F2) and the third largest (F3) follicles of the ovary at various times up to 23h after the hypophysectomy was estimated by the uptake of Sudan dye. The incidence of follicular atresia was also checked at the same time. The results indicate that the yolk deposition lasts longer in the estrogen-treated hens than in hens treated with no estrogen, and that the incidence of atresia was lower in the estrogen-treated hens. It is suggested that estrogen maintains yolk deposition and delays the incidence of atresia in the absence of pituitary hormones as far as the three largest follicles are concerned.