The Effect of Hypophysectomy on the Quail's Oviduct Response to Low and High Doses of Estradiol Benzoate*

Abstract

The response of the quail''s (Coturnix coturnix japonica) oviduct to different doses of estradiol benzoate (EB) was explored in ovariectomized and ovariectomized-hypophysectomized animals. Doses of EB ranged from 10 .mu.g to 1 mg/animal daily for 6 consecutive days; animals were sacrificed 24 h after the last injection. Controls were injected with olive oil. Parameters thought to reflect stimulation of the oviduct were wet and dry wt, DNA, RNA, soluble proteins, ovalbumin and morphological changes at the level of magnum''s mucosa. A statistically significant difference in several of the parameters listed was found between the effect of different doses of EB and whether the injection was done in ovariectomized or in ovariectomized-hypophysectomized animals. The dose response with EB for cell proliferation and induced proteins accumulation (ovalbumin) show that it takes considerably more EB to maximally stimulate ovalbumin accumulation when compared with cell proliferation. Hypophysectomy decreased the oviduct responses to high EB doses. Ultrastructural studies of the magnum mucosa confirmed these biochemical results. An EB dose-dependent different induction of specific cellular responses in the presence and absence of the pituitary in quails may be the basis to postulate the contributing role of the pituitary in the parameters measured.