Immunolocalisation of oestrogen receptors alpha (ERα) and beta (ERβ) in porcine embryos and fetuses at different stages of gestation

The sites of oestrogen action can be shown by the localisation of their receptors in the target tissues. The aim of the present study was to show the localisation of oestrogen receptors in porcine embryos and fetuses obtained on days 18, 22, 32, 40, 50, 60, 71 and 90 post coitum (p.c.). The visualisation of proteins was conducted in embryos and various fetal organs such as gonads, uterus, lung, kidney, intestine and adrenal gland. Both ERs were observed in the blastocysts on day 18 p.c. In the male, ER beta was detected in the testis and epididymis, whereas ER alpha was present in the efferent ductules. In the female, ER beta was detected in the ovarian stromal cells investing the oocyte nests, while ER alpha protein was detected in the surface epithelium. In the uterus, ERs were present in the stromal cells, while ER beta was present in the luminal epithelium. In the non-reproductive fetal porcine tissues ER beta was localised in the lungs, kidneys, adrenal glands and in the umbilical cords. Both ERs were observed in the intestine. It is possible that ER beta may play important roles in the development of the adrenal gland, testis, kidney and lungs, while both ERs are involved in the development of the ovary, uterus, epididymis and intestine of the porcine fetus.