Adrenal gland modulates oestrogen requirement for implantation in the rat

The effect of adrenal steroids upon implantation was evaluated by examining the efficacy of oestradiol-17 beta on the initiation of implantation in ovariectomized, ovariectomized plus adrenalectomized or hypophysectomized pregnant rats treated with progesterone. More oestrogen (X 5) was required in ovariectomized animals to obtain results equivalent to those obtained with the other animal models.