POST-NIDATORY EFFECTS OF LUTEINIZING-HORMONE RELEASING HORMONE (LHRH) IN HAMSTERS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 22  (3) , 184-188
Abstract
Whereas administration of LHRH to pregnant hamsters has no effect during the prenidatory period, the hormone is effective in terminating pregnancy when given after implantation (days 6-10). The ED50 for pregnancy termination over this period approximates a dose of 0.35-0.4 mg twice daily. When given to pregnant females in a 2nd study, the effects of LHRH at this dose were completely reversed by minute doses of progesterone (30 .mu.g and above). Finally, administration of LHRH at 1.5 mg twice daily from days 6-10 was followed by daily sacrifice through day 12; bloods were sampled at autopsy for progesterone evaluation. Autopsies on days 7 and 8 showed few differences between controls and LHRH-treated hamsters, although decreased weights of the uterine/conceptus units signaled the initiation of resorption. Significant LHRH-induced decreases in circulating progesterone were seen by day 9. Fetal resorption continued and was essentially complete by day 11, while progesterone levels continued depressed through the end of the study.