Effect of tri-iodothyronine and di-iodothyronine on lipid metabolism in a teleost Anabas testudineus Bloch

Intra-muscular injection of two doses of tri-iodothyronine (T-3) and di-iod othyronine (T-2) (100 ng and 200 ng) in female Anabas testudineus for a per iod of five days had a dose dependent effect on plasma Tg level, increase i n the activity of malic enzyme (ME) in liver and decrease in 6-phosphogluco nate dehydrogenase (6-PGDH) while there was no change in isocitrate dehydro genase (ICDH) and glucose 6-phosphate dehydrogenase (G6PDH) activity. H/M r atio decreased only by high doses of T-3 and T-2 indicating increased HMG C oA reductase activity. In cardiac tissue the activity of ICDH decreased whi le ME activity was unaltered. Lipid analysis showed increased catabolism of cholesterol to free fatty acids. These observation indicate that like T-3, T-2, a product formed by the monodeiodination of thyroid hormones, is also capable of causing lipid metabolism in this teleost.