SHORT-TERM EFFECTS OF 3,5,3'-TRIIODOTHYRONINE ON THE INTERMEDIARY METABOLISM OF THE DOGFISH SHARK SQUALUS-ACANTHIAS - EVIDENCE FROM ENZYME-ACTIVITIES

Plasma 3,5,3'-triiodothyronine (T-3) concentration decreased significa ntly (P < 0.05), during 1-5 days of captivity, from levels in the fres hly caught dogfish shark Squalus acanthias. The short-term effects of T-3 treatment on the intermediary metabolism of S. acanthias were meas ured in the gill, kidney, liver, and white muscle. Animals were kept f or 1-5 days before experimentation. Three hours after an intraperitone al injection with either a low T-3 dose (8.3 pmol T-3/ kg fish) or a h igh T-3 dose (830 pmol T-3/kg fish), selected enzymes of amino acid me tabolism, lipid catabolism, ketone body metabolism, glycolysis, and ox idative metabolism were measured. Activity of enzymes of amino acid me tabolism and lipid catabolism increased significantly (P < 0.05) in th e liver of fish treated with a low T-3 dose. The low dose of T-3 appar ently influences glycolysis as pyruvate kinase activity significantly increase (P < 0.05) in the kidney and white muscle. (C) 1996 Wiley-Lis s, Inc.