| Abstract: | The level of estrogen receptors (ER) in the cytosol and nuclear subfractions of female rat hepatocytes was studied 1 h and plasma angiotensinogen (AG) concentration 24 h after single and multiple administration of different doses of estradiol (E2) and synthetic estrogens. Synthetic weakly metabolized estrogens, used at doses corresponding to physiological concentrations of the natural female sex steroid, were shown to be much more effective than E2 in relation to ER redistribution between the cytosol and nuclear fractions of hepatocytes as well as in relation to the stimulation of AG production by the liver. Differences in the ER level in hepatocytic nuclei 1 h after single or multiple administration of the same estrogen were undetectable. An increase in a plasma AG level after a single injection of estrogens was noted after achieving a certain threshold (more than 3-fold as compared to the normal level) level of ER accumulation in hepatocytic nuclei. The sensitivity of AG production by the liver to a stimulating effect of low doses of estrogens was on the increase as a result of their repeated effect in prolonged administration and combined administration of E2 and glucocorticoids. |
