RESUMO
Testosterone concentration was measured by radioimmunoassay in 30 samples of blood serum obtained five times at each 6 hours interval during 24 hours from 6 Jaffarabadi x Mediterranean buffalo bulls. Blood samplings were carried out twice, respectively, in one day of summer and one day of winter season. Testosterone concentration ranged from 0.10 to 1.36 ng/ml in the winter day and from 0.10 to 2.54 ng/ml in the summer day. Maximum values were obtained at 6:00 p.m. (0.52) in summer and 0.82 ng/ml in winter, then abrupt drops occurred, first at 12 m. (0.37) in summer and 0.21 in winter, and the second one at 24 p.m. (0.17) in summer and 0.49 ng/ml in winter. In summer, higher serum testosterone levels were observed during the day.
Concentrações de testosterona foram determinadas por radioimunoensaio em 30 amostras de soro sangüíneo obtidas cinco vezes durante 24 horas, de 6 búfalos adultos Jaffarabadi x Mediterrâneo. As amostras foram obtidas durante um dia do inverno e um dia do verão de 1991. As concentrações de testosterona variaram de 0,10 a 1,36 ng/ml no inverno e de 0,10 a 2,454 ng/ml no verão. Valores máximos foram obtidos às 6,00 horas (0,52 ng/ml) no verão e 0,82 ng/ml no inverno, ocorrendo então duas quedas abruptas, a primeira às 12 horas (0,37 ng/ml) no verão e 0,21 ng/ml no inverno e a segunda 24 horas (0,17 ng/ml) no verão e 0,49 ng/ml no inverno. No verão, níveis mais altos de testosterona sérica foram observados durante o dia.