We examined the ability of ICI 182,780 (ICI) to block uterine cell proliferation via protein kinase b/AKT pathway in the uterus of the rat during the estrous cycle. Intact rats, with regular estrous cycles, received a subcutaneous (s.c.) injection of either vehicle or ICI at 08:00 h on the day of proestrus or at 00:00 h on the day of estrus and sacrificed at 13:00 h of metaestrus. Estradiol (E₂) and progesterone (P₄) plasma levels were measured by radioimmunoassay. Both ICI treatments, induced a significant decrease (p