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Biomedical subjects

Y Ehara

Publications and source records attributed to Y Ehara.

At least 55 records · Page 3Linked to original sources
PubMed1974

Augmentation of prolactin secretion by estrogen in hypogonadal women.

The effect of estrogen on prolactin (PRL) release and gonadotropin suppression was assessed in six experiments performed on four hypogonadal women. Ethinyl estradiol at a dose of 1 microgram/kg per day induced a significant elevation of serum PRL levels within the 1st wk of treatment. There was a further rise until a plateau was reached in about 3-4 wk to levels of more than 3 times the initial concentration. This was accompanied by a pattern of increased episodic fluctuation. The corresponding serum luteinizing hormone and follicle-stimulating hormone fell progressively during the study period. These data indicate that a positive feedback relationship between estrogen and PRL release exists in humans.

Estradiol Congeners↗
PubMedDate not supplied

The effect of hepatic interposition on ovary-pituitary interaction.

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.

Animals↗