[Sex differences in the level of cytosol estrogen receptors in the rat liver].

The procedure designed for the estimation of estrogen receptors (ER) in rat liver cytosol using sodium thiocyanate was shown to be useful for differential quantification of the ER level in liver cytosol of male rats, containing the unusual estrogen-binding protein. The ER concentration in rat liver cytosol was shown to be a sex dependent feature: its content in male rats (55 +/- 4 fmol/mg of protein) was lower (p 0.001) than that in female rats (116 +/- 4 fmol/mg of protein). The differences in the ER content were revealed only after maturation and disappeared after hypophysectomy of adult rats. Gonadectomy of males performed on the 1st postnatal day or in the pre- or postpubertal period resulted in complete "feminization" of the ER content in these animals. Ovariectomy in female rats at all stages of ontogenesis did not influence the ER level in liver cytosol. It was concluded that androgens have no programming, but only a negative regulatory influence on the ER level in rats.