The acute changes in hormonal profile were investigated in female rats after portacaval anastomosis. Surgery was performed in the morning of proestrus on rats with a 4-day estrus cycle and animals were decapitated at various times up to 9 days after surgery. The immediate afternoon surges of luteinizing hormones (LH), follicle-stimulating hormone (FSH), and prolactin (PRL) and the associated ovulation were not affected by the surgery. From the next day on, circulating levels of estradiol, progesterone, and androgens increased monotonically with time. Levels of 20α-dihydroprogesterone were relatively unchanged. Therefore, ratio of progesterone/20α-dihydroprogesterone became progressively higher, suggesting enhanced luteal steroidogenic activities. Corticosterone levels were either the same as the controls or lower. Although tonic levels of FSH and LH were not affected by the anastomosis, subsequent LH and FSH surges and ovulations failed to occur. These rats showed persistent vaginal mucous smears, and levels of afternoon (1830 h) PRL were elevated. Serial sections of ovaries revealed medium-sized follicles and well-luteinizing corpora on 4, 5, and 9 days after the surgery, suggesting that a) the failure of these rats to ovulate further may be due to the absence of subsequent preovulatory surges of LH and/or FSH probably blocked by the high levels of serum progesterone, and b) portacaval anastomosis prolonged luteal function by eliciting PRL release, possibly by means of elevated serum estradiol levels. An additional study was performed measuring PRL, estradiol, progesterone and corticosterone at 0530, 1200, and 1830 h at 5 days after the anastomosis in rats at proestrus and also in 5-day pseudopregnant rats. The results indicate that reduced hepatic function by portacaval anastomosis in female rats leads to a prolonged luteal phase that is different from that of genuine pseudopregnancy.
|Original language||English (US)|
|Journal||American Journal of Physiology - Endocrinology and Metabolism|
|State||Published - 1983|
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Physiology (medical)