Steroid hormones in the plasma of salmon at various states of maturation

Abstract

The plasma concentrations of all the major steroids thus far isolated from sockeye salmon were determined on fish captured at various stages of sexual maturity. The same steroids were determined in the plasma of spawned Atlantic salmon of both sexes. The data are discussed in relation to previous studies on liver glycogen levels and the source of energy expended by migrating salmon. There is a quantitative change in certain plasma steroids which coincides with the beginning of the river phase of the spawning migration. The results give some support to a “hormone trigger theory” for spawning migration. 11-Ketotestosterone was shown to have no significant effect on the deposition of liver glycogen in the adrenalectomized rat. This observation is discussed in relation to an apparent discrepancy in a previous determination of plasma steroids in Atlantic salmon by chemical and biological assay.