STUDIES ON THE MECHANISM OF DECIDUALIZATION. I.

Abstract

ABSTRACT The concept of an oestrogen surge as a prerequisite for successful decidualization of the progravid uterus and consequently nidation in the rat was tested. Experiments were designed to see whether administration of an oestrogen antagonist at specific times would block decidualization (and nidation); whether the ovary was the source of the oestrogen, and whether a single dose of oestrogen, in the absence of the ovary (if the ovary is the source) would allow the uterus to respond to a decidualizing stimulus. It was found that when given prior to the surge, the oestrogen antagonist prevented decidualization and interfered with nidation. The ovary is thus the source of the oestrogen; and a single injection of oestradiol can act as a substitute for the surge.