Effects of Reproductive Status, Ovariectomy and Sex Steroid Administration on Estrogen and Progesterone Receptors in the Uterus of Camel

Sections of camel uterus stained with immunoperoxidase for demonstration of estrogen and progesterone receptors showed that receptors for the two hormones were confined to epithelial nuclei. Staining intensity was stronger for progesterone receptors during estrus and pregnancy but weaker for estrogen receptors during pregnancy. In ovariectomized camels intramuscular administration of estradiol benzoate at a dose of 5 mg animal-1 increased uterine progesterone and estrogen receptor concentrations. Administration of progesterone at a dose of 100 mg per animal decreased steroid receptor concentrations. It is suggested that in the camel, uterine steroid receptors are up-regulated by estradiol and down-regulated by progesterone.