The Effect of Thyroid Hormone on the High Affinity Ca2+-ATPase in Rat Liver Plasma Membrane
1984 Volume 31 Issue 2 Pages 141-149
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1984 Volume 31 Issue 2 Pages 141-149
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 70μM 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.
