2.2. Testosterone radioimmunoassay in males

Trunk blood was collected from males when they were later euthanized at PND 90. Serum was used to determine circulating testosterone according to the manufacturer’s protocols (MP Biomedical; Testosterone ¹²⁵I RIA, Catalog #07189102). Littermates that were not behaviorally characterized were included in testosterone analysis. The assay sensitivity was 0.03 ng/ml and the average intra-assay variability was 1.56%. This assay is not sensitive enough to measure serum testosterone in females.