Antiluteinizing Hormone: Chronic Influence on Steroid and Gonadotropin Levels and Superovulation in the Pregnant Hamster*

Abstract

Pregnant hamsters were injected with either normal horse serum (NHS) or equine antibovine LH (ALH) and autopsied 4 days later (day 1 of pregnancy = sperm positive). Pregnancy was interrupted by a single sc injection of 0.1 ml ALH on days 4, 8, or 10. On days 6 and 12, 0.2 ml ALH was needed to interrupt pregnancy; however, ALH was only partially effective on day 12. After ALH on days 4 or 8 of pregnancy, corpora lutea on days 8 and 12 had regressed and serum progesterone (P) levels were less than 2 ng/ml. However, serum estradiol levels and the number of antral follicles (AF) were not different from NHS controls. There were approximately 11 AF/ovary and 17 AF/ovary in the days 4 and 8 groups, respectively; 4–9 days after ALH, spontaneous superovulation of 23 ± 3 (day 4 group) and 29 ± 4 (day 8 group) ova was observed. In contrast, the rat ovulates only 12.5 ± 0.3 (n = 11) ova after injection of the same ALH (0.2 or 0.5 ml) on day 8 of pregnancy. Serum levels of FSHlike material in ALH-treated hamsters were...