Diurnal variation of peripheral plasma levels of testosterone in bulls measured by a rapid radioimmunoassay procedure
Sanwal, P.C.; Sundby, A.; Edqvist, L.E.
Acta Veterinaria Scandinavica 15(1): 90-99
1974
ISSN/ISBN: 0044-605X PMID: 4830073 Document Number: 77704
A radioimmunoassay technique, using antibodies to testosterone-3-(O-carboxymethyl)oxime-bovine serum albumin, was used to measure peripheral plasma levels of testosterone in bulls. The individual as well as the mean 24-hour pattern of peripheral plasma levels of testosterone in the four bulls studied showed three distinct peaks. The mean peripheral plasma level of testosterone peaked around 10 p.m., around 6 a.m. and around noon, the mean levels obtained at these times being 6.2, 6.1 and 4.2 ng/ml, respectively. In one bull an additional peak occurred around 2 a.m. (8.2 ng/ml). Significantly lower peripheral plasma levels of testosterone were observed between the peak values.