Validation of radioimmunoassay systems for the measurement of 11-keto- and 11 beta-hydroxytestosterone in teleost blood.

Highly specific antisera for 11-keto- and 11 beta-hydroxytestosterone have been raised in sheep. Assay systems for the simultaneous measurement of 11-ketotestosterone, 11 beta-hydroxytestosterone, testosterone, progesterone and estradiol-17 beta were validated for Ictalurus nebulosus plasma and Carassius auratus serum. In males of both species 11-ketotestosterone and testosterone were the major steroids detected. In females, testosterone and estradiol-17 beta were the predominant steroids measured. Data from samples taken at different stages of the annual cycle suggest that seasonal fluctuations in gonadal steroid secretion occur in I. nebulosus and C. auratus.