Changes in plasma estrogen, luteinizing hormone, follicle-stimulating hormone and 13,14-dihydro-15-keto-prostaglandin F2 alpha during blockade of luteolysis in pigs after human chorionic gonadotropin treatment.
An injection of human chorionic gonadotropin (HCG) or estrogen on d 12 of the estrous cycle delays luteolysis in the pig. In an experiment to determine if HCG stimulated estrogen secretion, 21 cyclic pigs received one of five different amounts of HCG-(A) 0, (B) 125, (C) 250, (D) 500 or (E) 1,000 IU-as a single, im injection in 2 ml of distilled water on d 12 of the estrous cycle. Blood was collected from the jugular vein immediately before HCG injection and once daily thereafter until d 20 of the estrous cycle. Plasma progesterone, estrogen (unconjugated) and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) were quantified for pigs in all groups; luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were quantified for pigs in groups A and E. The HCG injection exerted a dose-related increase on the mean interestrus interval (groups A, B, C, D and E were 20.5, 20.2, 22.5, 31.0 and 61.4 d, respectively) and on the delay of luteolysis as measured by mean plasma progesterone on d 16 (A, B and C vs D and E, respectively, 1.9, 1.2 and 10.4 vs 34.1 and 47.1 ng/ml; P less than .05). The HCG injection caused a transitory increase in plasma estrogen from d 12 (5 to 10 pg/ml before treatment) to d 15 (35.5 pg/ml, group D) and to d 16 (90.2 pg/ml, group E) before it decreased to preinjection levels on d 17 (group D) and 18 (group E).(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage / Q000494:pharmacology*; D003338:Corpus Luteum / Q000187:drug effects*; D003340:Corpus Luteum Maintenance; D015237:Dinoprost / Q000031:analogs & derivatives*; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011460:Prostaglandins F / Q000097:blood*; D013552:Swine / Q000502:physiology*
D006063:Chorionic Gonadotropin; D004967:Estrogens; D011460:Prostaglandins F; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D015237:Dinoprost