IN VIVO METABOLISM OF STEROID HORMONES BY SOCKEYE SALMON: (A) IMPAIRED HORMONE CLEARANCE IN MATURE AND SPAWNED PACIFIC SALMON (O. NERKA) (B) PRECURSORS OF 11-KETOTESTOSTERONE

Abstract

Intra-arterially injected cortisone-4-C14and cortisol-4-C14were cleared from the plasma of sexually mature and spawned sockeye salmon (O. nerka) at a much slower rate than from the plasma of immature sockeye and spawned Atlantic salmon (S. salar). The results explain the elevated hormone levels found in the blood of mature and spawned sockeye salmon. The normal clearance rate found with Atlantic salmon, which frequently survive spawning, would indicate that the impaired hormone metabolism was associated with the imminent death of the Pacific salmon rather than with the act of spawning.Testosterone and 17α-hydroxyprogesterone were found to be precursors of 11-ketotestosterone, a sex hormone found in high concentrations in the blood of mature sockeye salmon. Testosterone was also formed in vivo from 17α-hydroxyprogesterone. The results suggest more than one pathway for the synthesis of 11-ketotestosterone in salmon. Cortisol was converted to cortisone but no conversion of the former to 11-ketotestosterone could be demonstrated.