抄録
Levels of serum progesterone (P) and LH were determined daily in pregnant rats from Day 4 through parturition.In other pregnant rats the effect of antisera to LH (LH-A/S) and to LRF (LRF-A/S) on serum P, LH and fetal development were determined. These animals were treated with antisera on Days 8 through 10.Samples of blood were obtained on Day 8 before treatment started and again on Days 11 and 15.The animals were sacrificed on Day 15 and examined for fetal development and the ovaries weighed.
In untreated pregnent rats, the level of serum P showed two peaks, one on Day 7 and the other on Day 16.Serum P dropped acutely shortly before delivery.Serum LH showed no significant peaks through pregnancy but fluctuated between 30 and 160ng/ml.
In rats receiving 0.2ml LH-A/S s.c.on Days 8-10, the serum P was reduced to nondetectable levels on Day 11 and had recovered only slightly by Day 15. Pregnancy was terminated in all instances and the ovarian weights were reduced. Lower doses of LH-A/S were ineffective. Rats receiving 1.3ml of LRF-A/S on Days 8-10 showed no effect on serum P, or LH and no injurious action on fetal development.Lesser amounts of this LRF-A/S (0.8ml) were known to block the proestrous gonadotropin surge and inhibit ovulation in cycling rats.These findings confirm that LH is an essential component of the luteotropic complex during early pregnancy in the rat.They also suggest that a basal of LH and P can be to some extent maintained in rats treated with LRF-A/S during early gestation.
