Analysis of the Expression of Estrogen and Progesterone Receptors in the endometrium of ewes of the races Romney Marsh and Araucana/Analisis de la expresion de receptores de estrogenos y progesterona en el endometrio de ovejas de las razas Romney Marsh y Araucana

The morphofuncional state of the genital tract of females ewes is determined by sexual hormones, those that act through specific receptors. These regulate the expression of numerous proteins that participate in the development of the endometrium. Possibly the reproductive performance of different races from ewes could be determined by the expression differential of the receptors. The objective of the present study was to analyze the presence of estrogen receptors (RE) and progesterone receptors(RP) in the endometrium of prepuberal and cycling ewes of the races Romney Mash and Araucana. The histhologic study of endometrium was made in cross sections of 5 mm stained with hematoxilina-eosin. The presence of both receptors is detect by immunohistochemical study using monoclonal antibodies. In addition we evaluated by Dot-blot the presence of receptors in total protein extracts obtained from endometrial tissue Inmunoreaction signal against both receptors in lambs was detected and in adults cicling of both races The positive inmunoreaction is localizate in nuclei of estromales and glandular epitelium cells. The RE in adult ewes showed greater expression that in prepuberal, without significant differences between both races. The RP gave positive inmunoreaction in both races, being the signal more marcate in Romney Marsh lambs , while that in adult ewes higher signal was observed in Araucanas. We conclude that the immunohistochemistry expression of RE and RP is always detectable in the endometrium of the ewes varying his expression according to its development and reproductive stage, not significant differences were observed between both races.