[Role of estrogens in the induction and regulation of a specific estrogen-binding protein in the rat liver].

A study was made of the role of estrogens (E) in the induction and regulation of the level of specific estrogen binding protein (SEBP) in the rat liver using a differentiated quantitative method of its determination. It was shown that E could not replace androgens (A) in the primary determination of the SEPB level, neither did they prevent its A-dependent induction. Multiple administration of 0.4 microgram of estradiol (E2) caused a significant decrease in the SEPB level in intact and castrated male rats as well as in ovariectomized females with the A-induced SEPB level. Multiple administration of even 10 micrograms of E2 did not influence the SEPB level in hypophysectomized males. The rate of development of the E2 effect on the SEPB level of the mature male liver increased with the growth of the dose and duration of hormone administration. The inhibitory effect of E2 was also revealed in a single administration of 10 micrograms of the hormone. In that case the effect was observed after a 3-day lag period, and a maximum decrease in the SEPB level occurred in 6 days. The regulatory negative effect of E2 was reversible. Complete regeneration of the initial SEPB content took place 10-12 days after the development of the maximum effect of E2.