SOMATOLACTIN AND GROWTH-HORMONE ARE DIFFERENTIALLY CORRELATED TO VARIOUS METABOLIC PARAMETERS IN TROUT

The effect of starvation on plasma hormone and metabolite levels in ra inbow trout (Oncorhynchus mykiss) was investigated. Plasma somatolacti n (SL) levels were found to be significantly lower in starved than in fed fish, whereas plasma growth hormone (GH) levels were significantly elevated during starvation. Changes in plasma free fatty acids, gluco se, protein, amino acids and liver glycogen occurred as expected in th e starved fish. Regression anal!;sis indicated that both SL and GH iel -els were significantly correlated to most of the metabolic parameters measured; however: the regression lines for SL and GH were always opp osite to each other. The results indicate that SL, as well as GH, may be involved in some aspect of energy metabolism control.