title: Biliary elimination of endogenous nortestosterone by pregnant cows.
abstract: A temporal study of the biliary elimination of endogenous 19-nortestosterone during two successive pregnancies was made in three cows with cannulated gall bladders. Bile samples were analysed for 17 beta-19-nortestosterone (beta-NT) and the 17 alpha-epimer (alpha-NT) by using high resolution gas chromatography and mass spectroscopy. No beta-NT was detected in any of the samples analysed. However, alpha-NT was detected from around 120 days of gestation in each of the cows. Peak concentrations were observed in the last week before calving and ranged from 9.5 to 36.7 ng/ml. After parturtion, the concentrations of alpha-NT declined rapidly and were undetectable by seven days after calving, and it was not detected again until after 120 days of gestation. The biliary concentrations of alpha-NT detected subsequently were similar to those observed in cattle several weeks after an exogenous injection of the synthetic ester beta-NT phenylpropionate.
authors.affiliation: Residues Department, Department of Agriculture for Northern Ireland, Belfast.
authors.forename: J D
authors.initials: JD
authors.lastname: McEvoy
authors.forename: C E
authors.initials: CE
authors.lastname: McVeigh
authors.forename: W J
authors.initials: WJ
authors.lastname: McCaughey
authors.forename: S A
authors.initials: SA
authors.lastname: Hewitt
mesh_terms: D000818:Animals; D001659:Biliary Tract / Q000502:physiology*; D002417:Cattle / Q000502:physiology*; D002849:Chromatography, Gas; D005260:Female; D007743:Labor, Obstetric; D009277:Nandrolone / Q000032:analysis / Q000378:metabolism*; D049590:Postpartum Period; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*
chemical_list: D009277:Nandrolone