Testosterone metabolism and testosterone-dependent characteristics in Japanese quail

In 2 independent experiments, we measured and correlated in maturing male Japanese quail the individual variations in sexual and aggressive behavior, cloacal gland size, testes weight, plasma testosterone concentrations and intracellular testosterone metabolism by hypothalamus and cloacal gland. Cloacal gland area was only weakly related to plasma testosterone levels but was positively correlated with the production of active androgenic metabolites and negatively related to the production of 5 beta-reduced androgens (inactive) in the glandular tissue. Several measures of behavior were correlated with aspects of the testosterone metabolism in the anterior hypothalamus. In both experiments, the behavior of the birds was also strongly correlated with their testes weight and their cloacal gland area but weakly or not at all with their plasma testosterone levels. These studies suggest that testosterone metabolism is involved in the control of hormone action in maturing animals.