Prolonged effect of a single injection of human chorionic gonadotrophin on plasma testosterone and oestrone sulphate concentrations in mature stallions.
The long term effect of a single injection of 6,000 iu of human chorionic gonadotrophin (hCG) was studied in two pony stallions. Peripheral plasma samples were analysed for testosterone and oestrone sulphate. Testosterone concentrations were markedly elevated for five days after injection in both stallions. No adverse effects of these high concentrations were observed on concentrations later in the experiment. There was an initial increase in oestrone sulphate in one stallion, after which concentrations decreased to below pre-injection levels. The other stallion (whose initial oestrone sulphate concentrations were somewhat higher) showed no rise in response to hCG but did show a significant decline from five days after injection. Whether this suppression is an effect of the high testosterone concentrations remains to be determined.
Cox
J E
JE
Department of Veterinary Clinical Science, University of Liverpool Veterinary Field Station, Neston, South Wirral.
Redhead
P H
PH
D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage / Q000494:pharmacology*; D004966:Estrogens, Conjugated (USP) / Q000097:blood*; D004970:Estrone / Q000031:analogs & derivatives* / Q000097:blood; D006736:Horses / Q000097:blood*; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D013739:Testosterone / Q000097:blood*
D006063:Chorionic Gonadotropin; D004966:Estrogens, Conjugated (USP); D004970:Estrone; D013739:Testosterone; C017296:estrone sulfate