Abstract
Summary
A high dose of ICSH (100 μg in gelatin daily for 5 or 6 days) in Long-Evans rats hypophysectomized (H) on Days 7, 8 or 9 of pregnancy induced hyperluteinization in the ovaries. The usual number of 10–12 corpora lutea of pregnancy were found and also about twice that number of theca-luteinized corpora. This latter finding, and the presence of stimulated ovarian follicles showed that the ICSH had a minor but significant contamination with FSH in a ratio that could be expected to induce estogen secretion.
All 4 rats H on Day 7 and injected for 6 days with ICSH showed resorbing sites, and no living fetuses on Day 13. Of 14 rats H on Day 8 and injected for 5 days with ICSH, nine showed living fetuses (av 11) on Day 13. Of 5 rats H on Day 9 and injected for 5 days with ICSH, all showed living fetuses (av 10) on Day 14.
Since rat chorionic mammoluteotropin (RCM) secretion begins on Day 7; and increases to a peak on Day 12, it would seem that its luteotropic activity was responsible for adequate amounts of progesterone in cases of successful maintenance of pregnancy. Undoubtedly the ICSH plus FSH combination induced the necessary small amount of estrogen to be secreted; and this in turn may have induced the placenta to secrete increased levels of RCM.
Get full access to this article
View all access options for this article.