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pubmed:abstractText |
When the livers of female rats were provided with exclusive first access to all ovarian venous effluents by simultaneous castration and implantation of a portion of one of the ovaries beneath the splenic capsule, systemic venous plasma concentrations of estrone and estradiol were reduced 40%. Paradoxically, progestins in the peripheral plasma increased threefold, most probably because of augmented adrenocortical progestin secretion. Nevertheless, the change in estrogen levels alone was sufficient to abolish trophic effects on the genital organs and to block normal inhibition of pituitary gonadotropin secretion. Plasma gonadotropin concentrations were markedly elevated to levels comparable to those of castrates, and, as a result, the intrasplenic ovarian implants grew excessively and became histologically disorganized. A patent portacaval shunt negated the entire process, providing proof that the measured hormonal alterations and the change in the implant itself were direct consequences of hepatic screening.
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