Steroid Hormone Receptors: Localization in Pig Oviducal Cells

PERALTA, LUISA; MARIELA ROLDÁN OLARTE; FERNÁNDEZ DE BRUNETTI, SILVIA; MICELI, DORA C.

Tafi del Valle, Tucuman, Argentina

Jornada; XII Jornadas Científicas de la Sociedad de Biología de Tucumán; 1995

Sociedad de Biologia de Tucuman

It was found evidences that steroid hormones can act through an extragenomic mechanism, in which a second messenger would be involved. In this work we studied this possibility in pig oviducal cells. The specific binding was determined in the whole cells and in the cell membranes. The membrane fraction was obtained by centrifugation and checked by 5’ nucleotidase activity and electronic microscopy. The binding activity was measured by incubation with H-estradiol , H-testosterone and R5020 and displaced with cold DEES, DHT and R5020 at 100-200 fold concentrations. Our results shows that the cells bound estradiol specifically and in a saturable way. Incubation of one hour, at 37 °C, with mixing gave a specific binding of 92%, meanwhile specific binding of testosterone and R5020 was negligible. Membrane fraction bound also specifically 17- b- estradiol and R5020 when are incubated for one hour , but incubating at 0 °C. The presence of specific receptors at cell membrane level would indicate a possible extragenomic mechanism of these steroid hormones.