The effect of thyroid hormone on the high affinity Ca2+-ATPase in rat liver plasma membrane.
The effect of thyroid hormone on the high affinity Ca2+-ATPase activity in rat liver plasma membrane was studied. The high affinity Ca2+-ATPase activity in plasma membrane was activated by 10(-7)-10(-5) M of Ca2+ and was inhibited by 70 microM trifluoperazine. Thyroidectomy of rats was associated with an increase in the activity of high affinity Ca2+-ATPase. The increased enzyme activity was normalized by T4 administration to the animals. On the other hand, Na+-K+-ATPase activity in the membrane was decreased by thyroidectomy and the decreased enzyme activity was normalized by T4 administration. The results suggest that thyroid hormone inhibits the Ca2+ extrusion system by inhibiting calmodulin-independent high affinity Ca2+-ATPase in liver plasma membrane.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013963:Thyroid Hormones / Q000494:pharmacology*; D013965:Thyroidectomy; D013974:Thyroxine / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D013963:Thyroid Hormones; D014284:Triiodothyronine; D014268:Trifluoperazine; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D013974:Thyroxine; D002118:Calcium