Different responses of rat endometrial epithelium and stroma to induction of oestradiol binding sites by progesterone.

Rats were ovariectomized for 3 weeks and then treated for 3 days with 4 mg progesterone. The cytosolic oestradiol receptor content in the stroma cells was very high (approximately 21,000 binding sites/cell) as compared with that in the epithelial cells (approximately 3000 binding sites/cell). The nuclear receptor values were low (approximately 500 binding sites/cell) in both types of cell.