These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Comparison of the effects of injections of nortestosterone phenylpropionate at single and multiple sites in cattle on the detection of its residues in plasma, urine and bile.
    Author: McEvoy JD, McVeigh CE, McCaughey WJ, Kennedy DG.
    Journal: Vet Rec; 1999 Jan 09; 144(2):42-7. PubMed ID: 10028584.
    Abstract:
    The synthetic androgen 17 beta-19-nortestosterone (beta-NT) has been used illegally as a growth promoter in cattle production in the European Union. The elimination of beta-NT and its metabolites in plasma and urine was studied in cattle which had received intramuscular injections of its phenylpropionate ester (NTPP) at either single or multiple sites at a dose rate of 1 mg/kg bodyweight. In both groups, the plasma concentrations of beta-NT, measured by enzyme immunoassay, were consistently greater than the assay's limit of quantification (0.24 ng/ml) during days 1 to 7 of the study. The mean (sd) maximum plasma concentration (Cmax) was significantly greater in the multiply injected animals (4.4 [0.48] v 2.7 [0.15] ng/ml), but other plasma pharmacokinetic parameters, AUC, CL, T1/2 beta, Tmax and MRT, were not significantly different in the two groups. The equivalent urinary concentrations exceeded the limit of quantification of the assay (4.5 ng/ml) for up to 24 days after injection. In a second study, the biliary concentrations of beta-NT and its 17 alpha-epimer (alpha-NT) were measured by gas chromatography-high resolution mass spectrometry after cattle were injected intramuscularly at either single or multiple sites with NTPP. Only alpha-NT was detected in bile for up to 62 days after injection at concentrations above the limit of quantification of the assay (0.7 ng/ml). It is concluded that in some animals, intramuscular injections of NTPP at several sites may decrease the period after injection during which free beta-NT and its metabolites are detectable in plasma and urine. After the injection of NTPP, alpha-NT was detected in bile for longer than it was detected in plasma or urine.
    [Abstract] [Full Text] [Related] [New Search]