EFFECTS OF TOPICAL AND SYSTEMIC ESTROGEN ON MORPHOLOGY OF PORCINE UTERINE LUMINAL EPITHELIA

Silastic beads containing either estradiol-17-beta or cholesterol were surgically introduced into the uterine lumina of gilts on Day 10 postestrus, and the animals were killed on Day 13 or 19 (n = 4/day/treatment). An additional group of gilts were injected i.m. with 5 mg estradiol valerate on Days 11-15 of the estrous cycle and were killed on Day 13 and Day 19 (n = 4/day). Endometrial samples were collected and prepared for light and electron microscopic study. Cholesterol beads did not appear to affect endometrial structure. Both intrauterine and systemic treatment of gilts with estradiol induced folding along the mesometrial region of the uterus similar to that which occurs during early pregnancy. The uterine luminal epithelium of animals exposed to both exogenous hormone treatments exhibited morphological features similar to those of this layer during early pregnancy: evidence of increased synthetic and secretory activity, decreased incidence of cell degeneration, accumulation of glycogen and dense inclusions, variation in nuclear position, and elaboration of a thick fibrous glycocalyx.