title: Thyroid hormone-induced changes in different ion-specific adenosine triphosphatase activities in liver of Singi fish Heteropneustes fossilis (Bloch).
abstract: A single injection of different doses of T3 (0.5, 5, 20, and 50 micrograms/g) to Singi fish caused an increase in Na+K+-ATPase activity in crude liver homogenate in a dose-dependent non-linear fashion on the 3rd d. Ca++- and Mg++-ATPase activity increased only with 20 and 50 micrograms/g of T3. Lowering the dose of T3 to 0.1 microgram and 0.25 microgram/g in a single injection had not effect on these enzyme activities. TETRAC (1, 2, and 4 micrograms/g) and TRIAC (2 and 4 micrograms/g) in a single injection enhanced the activities of Na+K+-ATPase, but Ca++- and Mg++-ATPase activities remained unchanged on the 3rd d. Immersion of Singi fish in thiourea-containing medium (1 mg/ml) for 30 d caused reduction in Na+K+-ATPase activity, but Ca++- and Mg++-ATPase activity remained unaltered. The reduced level of Na+K+-ATPase activity in the thiourea-treated hypothyroid fish was recovered and even brought above the control level by a single injection of T3 at the dose of 0.5 microgram/g. Differential sensitivity of various ion-specific ATPases to T3 in liver of Singi fish is thus documented.
mesh_terms: D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002397:Catfishes / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013963:Thyroid Hormones / Q000494:pharmacology*; D013974:Thyroxine / Q000031:analogs & derivatives / Q000494:pharmacology; D014284:Triiodothyronine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D013963:Thyroid Hormones; D014284:Triiodothyronine; C010642:3,3',5-triiodothyroacetic acid; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; C011126:tetraiodothyroacetic acid; D013974:Thyroxine