Endocrinology, Vol 102, 494-498, Copyright © 1978 by Endocrine Society
Preprogramming mechanism of luteinizing hormone in the determination of the lifespan of the rat corpus luteum
M Takahashi, K Shiota and Y Suzuki
Luteal regression was studied in female rats bearing an isografted
pituitary under the renal capsule and the day of ovulation was designated
as day 0. These females had pseudopregnancy-like cycles and ovulations at
16-day intervals. After each ovulation, corpora lutea were activated and
progesterone concentrations increased in peripheral blood until day 5,
after which concentrations gradually decreased. Removal of the in situ
pituitary on day 0 or 1 resulted in maintenance of luteal function;
progesterone concentrations were sustained. This effect of hypophysectomy
on day 0 was prevented by daily administration of small amounts of LH from
days 0-5; however, luteal regression occurred if hypophysectomy was
performed on day 4 or later and progesterone concentrations decreased.
Luteal regression was prevented if anti-LH serum was administered from days
1-5 to pituitary-isografted rats and was followed by hypophysectomy on day
5. These results indicate that the lifespan of corpora lutea in
pseudopregnant rats is programmed between days 2-4 after ovulation through
the hypothalamohypophysial axis via secretion of LH.
