[In vivo effects of conjugated estrogens on the insulin receptor and on glucose binding in isolated adipocytes of male rats].

Studies have been carried out with labeled substrates on isolated adipocytes of male rats injected with sulpho-conjugated estrogens. Three days treatment did not affect insulin receptor concentration or affinity in the cells. Conversely glucose uptake is reduced in the absence of insulin, or by reduced responsiveness in the presence of it. After ten days treatment, insulin binding impaired on account of reduced receptor concentration, whereas glucose uptake was normal in the absence of insulin, increased at low and decreased at high insulin concentration, on account of both decreased responsiveness and increased sensibility to insulin. Thus it is suggested that estrogens acts on glucose uptake prior to act on the insulin receptor in the adipocytes.