Hormonal control of pinocytosis in the uterine epithelium of the rat

Abstract

Ovariectomized rats were treated with estradiol-17.beta. and/or progesterone to mimic the hormonal parameters inducing uterine sensitivity for implantation. The degree of pinocytosis of trypan blue and ferritin in the endometrial cells was examined. Significant epithelial pinocytosis of trypan blue occurred after a 3-day treatment of progesterone, and uptake was independently increased by priming with estrogen and by estradiol given on the 3rd day of progesterone treatment. Progesterone treatment caused uptake of ferritin by the epithelial cells; in control animals epithelial and stromal cells were involved. Estrogen priming enhanced ferritin absorption, while nidatory estrogen had no effect. Estradiol given alone completely blocked pinocytosis of both intraluminally injected substances.