The in vitro metabolism of testosterone by the brain and crest of domestic chicks

The in vitro metabolism of testosterone was studied in four different tissues, hyperstriatum, hypothalamus, pituitary gland and crest, of male and female domestic chicks at the age of 1 and 11 days. The metabolic pathways previously observed in other species of adult birds were present. The 53-reductase activity decreased markedly in males and females between the ages of 1 and 11 days.Several sexual differences were found in testosterone metabolism by its target organs. The biological significance of these metabolic pathways and their regulation is briefly discussed.