title: Levels of progesterone and changes in prostaglandin F(2alpha) release during luteolysis and early pregnancy in llamas and the effect of treatment with flunixin meglumine.
abstract: The secretory patterns of progesterone in relation to concentrations of 15-ketodihydro-PGF(2alpha) (PGFM) during the period of luteolysis or of maternal recognition of pregnancy were determined in the blood of llamas mated either with an intact or a vasectomized male. The ability of flunixin meglumine (FM) to postpone luteolysis in non-pregnant llamas was investigated by injecting the drug intravenously every 6 h at a dose of 2.2 mg/kg from days 6 to 12 post-copulation into a group of non-pregnant llamas. A pulsatile pattern of prostaglandin release was recorded during luteolysis in non-pregnant llamas, giving further support to the hypothesis that PGF(2alpha) is the luteolytic agent in llamas. The mean number of peaks per animal rose from 0.3 on day 7 to 3.8 on day 10 and then declined to 1.1 on day 12 with corresponding mean peak amplitude changing from 465 to 1234 and 566 pmol l(-1), respectively. In pregnant llamas, prostaglandin pulsatile release also occurred. The mean number of peaks per animal rose from 0.4 on day 7 to 0.8 on day 10 and then declined to 0.2 on day 11 and 0.6 on day 12, with corresponding mean peak amplitude changing from 494 to 676, 388 and 547 pmol l(-1), respectively. The transient decrease and subsequent recovery in progesterone concentrations was observed to occur in connection with prostaglandin release during early pregnancy. Oestradiol-17beta plasma peak concentrations attained after luteolysis were significantly higher than those recorded in early pregnant animals (around 30 pmol l(-1) and ll pmol l(-1)). Concentrations of PGFM decreased rapidly after the first administration of FM and remained low throughout the first 2 days of treatment. Thereafter, pulsatile release of prostaglandins started, and luteolysis proceeded; but a delay of 1-1.5 days in the progesterone decline was observed. Thus, it might be suggested that a higher dose and/or a more intensive injection schedule is required in llamas than in other ruminants to prevent luteolysis.
authors.affiliation: Department of Clinical Chemistry, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, P.O. Box 7038, S-750 07, Uppsala, Sweden. maba@vet.unicen.edu.ar
authors.forename: M A
authors.initials: MA
authors.lastname: Aba
authors.forename: H
authors.initials: H
authors.lastname: Kindahl
authors.forename: M
authors.initials: M
authors.lastname: Forsberg
authors.forename: M
authors.initials: M
authors.lastname: Quiroga
authors.forename: N
authors.initials: N
authors.lastname: Auza
mesh_terms: D000818:Animals; D002161:Camelids, New World / Q000502:physiology*; D003002:Clonixin / Q000031:analogs & derivatives* / Q000494:pharmacology; D003338:Corpus Luteum / Q000502:physiology*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood*; D004958:Estradiol / Q000097:blood; D005260:Female; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D011448:Prostaglandin Antagonists / Q000494:pharmacology*
chemical_list: D011448:Prostaglandin Antagonists; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D011374:Progesterone; D004958:Estradiol; C014558:flunixin meglumine; D015237:Dinoprost; D003002:Clonixin