Suppression of luteal function in dogs by luteinizing hormone antiserum and by bromocriptine.
Beagle bitches were treated with equine anti-LH serum (ALHS) or the dopamine agonist bromocriptine at selected times during the 2-month luteal phase of the ovarian cycle or pregnancy. After a single injection of ALHS (10 ml, i.m.) at Day 42 of pregnancy (N = 2) or the ovarian cycle (N = 3), progesterone was reduced (P less than 0.05) to 7-24% of preinjection values within 1-2 days, and by 4-8 days returned to levels not different from those in control bitches treated with normal horse serum. Injections of bromocriptine (0.1 mg/kg, i.m.) daily for 6 days caused abrupt declines in progesterone which lasted 6-8 days in bitches treated at Day 8 or 22 of pregnancy (N = 5). In bitches treated at Day 42 of pregnancy (N = 3) or in non-pregnant cycles (N = 4) the bromocriptine treatment caused declines (P less than 0.05) in progesterone which were permanent, extensive (less than 2 ng/ml), and therefore abortive. The declines in progesterone in response to immunoneutralization of LH and to prolactin-lowering doses of a dopamine agonist demonstrate that normal luteal function in dogs requires both LH and prolactin.
Concannon
P W
PW
Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
Weinstein
P
P
Whaley
S
S
Frank
D
D
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D003338:Corpus Luteum / Q000187:drug effects* / Q000276:immunology; D004285:Dogs / Q000502:physiology*; D005260:Female; D007106:Immune Sera / Q000494:pharmacology*; D008183:Luteal Phase; D007986:Luteinizing Hormone / Q000276:immunology*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood
D007106:Immune Sera; D001971:Bromocriptine; D011374:Progesterone; D007986:Luteinizing Hormone