Increased cell membrane permeability to Na+ and K+ induced by thyroid hormone in rat skeletal muscle.
Thyroid hormone (T3) increased Na+ dependent respiration accompanied by an increase in NaK-ATPase activity. Administration of T3 increased intracellular K+ concentration and Na/K ratio in thyroidectomized rats, and the Na+ efflux rate constant incubated in oxygenized Na+, K+-Ringers in euthyroid rats. However, the magnitude of the changes in intracellular K+ concentration was modest or invisible in comparison to the changes in QO2(t) and NaK-ATPase activity. The Na+ and K+ efflux rate constants in K+-free +ouabain Ringers were increased by T3 in both thyroidectomized and euthyroid rats. Thus, thyroid hormone stimulates not only Na pump but also the permeability of cell membrane to Na+ and K+. The both effects might contribute to the thyroid thermogenesis.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D066298:In Vitro Techniques; D009132:Muscles / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010101:Oxygen Consumption / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013963:Thyroid Hormones / Q000502:physiology*; D013965:Thyroidectomy; D014284:Triiodothyronine / Q000494:pharmacology
D013963:Thyroid Hormones; D014284:Triiodothyronine; D012964:Sodium; D000251:Adenosine Triphosphatases; D011188:Potassium