EFFECTS OF SOMATOSTATIN-25 ON LIPID MOBILIZATION FROM RAINBOW-TROUT, ONCORHYNCHUS-MYKISS, LIVER AND ADIPOSE-TISSUE INCUBATED IN-VITRO - COMPARISON WITH SOMATOSTATIN-14

The physiological effects of the pancreatic peptides somatostatin-14 and somatostatin-25 on lipid metabolism in rainbow trout were evaluated by in vitro culture of liver and adipose tissue. The culture medium was subsequently analyzed for glycerol and fatty acid content and triacylglycerol lipase activity was measured within the tissues. Both somatostatin-14 and somatostatin-25 stimulated hepatic fatty acid and glycerol release within 3 h after treatment. Liver triacylglycerol lipase activity was elevated following treatment with somatostatin-14 (76% above control) or somatostatin-25 (94% above control). Somatostatin-14 and somatostatin-25 also significantly stimulated the release of fatty acid and glycerol from adipose tissue. Triacylglycerol lipase activity in adipose tissue also was enhanced by both somatostatins. These results indicate that somatostatin-14 and somatostatin-25 directly stimulate the mobilization of triacylglycerol from liver and adipose tissue, suggesting that these peptides are important systemic modulators of lipid metabolism in fish.