Effects of an antiserum to luteinizing hormone and steroid replacement therapy on maintenance of pregnancy in the rat: serum and luteal levels of progesterone, testosterone and oestradiol.
Pregnant rats were injected s.c. with antiserum to LH (anti-LH) on days 8 or 10 of pregnancy (day 1 = day of sperm-positive vaginal smear) and subsequently given various steroids s.c. to prevent luteolysis and/or abortion. A single injection of 4 mg progesterone on day 8 prevented abortion and luteolysis as shown on day 12 by the presence of fetal swellings and levels of progesterone in serum (88 +/- 6 (S.E.M.) ng/ml) and corpora lutea (26 +/- 3 ng/mg) comparable to control values. After 0.5 ml anti-LH on day 10, a daily dose of 4 mg progesterone prevented abortion in five out of eight animals but by day 13 luteal progesterone was 3.0 +/- 0.7 compared with 24 +/- 3 ng/mg in controls. After anti-LH on day 8 or 10, daily injections of 1 or 4 mg testosterone propionate or 10 micrograms, 100 micrograms or 1 mg oestradiol failed to prevent abortion or to raise luteal concentrations of progesterone to normal values. However, 4 mg testosterone propionate on day 8 or 100 or 500 micrograms oestradiol on day 10 maintained serum progesterone levels at approximately half those of control values. Treatment with 4 mg testosterone propionate on days 8-11 led to significant increases in serum and luteal levels of testosterone and oestradiol on day 12; on day 10 exogenous oestradiol by day 13. These results, especially treatments begun on day 8, are difficult to reconcile with the current concept that the luteotrophic action of LH in the pregnant rat is exerted by increasing luteal androgens that are aromatized to oestrogens which then act as the direct luteotrophic stimulus.
D000818:Animals; D003338:Corpus Luteum / Q000187:drug effects / Q000378:metabolism*; D004958:Estradiol / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D007106:Immune Sera / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000502:physiology*; D011247:Pregnancy; D011255:Pregnancy Maintenance / Q000187:drug effects; D011374:Progesterone / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D013739:Testosterone / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology
D007106:Immune Sera; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone