[Relationship between testosterone binding proteins and testosterone and LH plasma concentrations in the young bull]

Plasma levels of testosterone and LH were measured by radioimmunoassay from blood samples of young bulls of 9 to 15 months of age. The binding constants of specific testosterone binding plasma proteins were determined from the same samples. No significant difference of these values could be seen during the 25 hr. sampling period, contrary to large fluctuations in testosterone and LH plasma concentrations. But, the testosterone binding constants values were significantly lower after puberty (15 months) than at 9 and 12 months of age.