CHANGES IN PLASMA 17-HYDROXYCORTICOSTEROIDS ACCOMPANYING SEXUAL MATURATION AND SPAWNING OF THE PACIFIC SALMON (ONCORHYNCHUS TSCHAWYTSCHA) AND RAINBOW TROUT (SALMO GAIRDNERII)

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Abstract
Plasma 17-hydroxycorticosteroids (17-OHCS) were determined in king salmon at successive stages of sexual development. Plasma samples taken at 2 points on the spawning migration showed a marked rise in the 17-OHCS in both males and females of 4-5 times the values found at sea. At spawning, females show a further rise whereas the concentration in males declines. Both hydrocortisone and cortisone were identified in the plasma of sexually mature salmon. Plasma concentrations of 17-OHCS were determined for spawning anadromous rainbow trout and analysis demonstrated the same corticoids as in the salmon. The progressive increase in the concentration of plasma 17-OHCS in the maturing female Pacific salmon resembles the pregnant human female. Plasma levels of corticoids in Cushing''s syndrome are approximately the same as those in sexually maturing salmon. The increasing concentrations of 17-OHCS in Pacific salmon blood as they progress from the sea to the spawning grounds parallels the degree of adrenal hyperplasia.