Effects of thyroxine treatment on the hepatic plasma membrane ATPase activity in rats.
J Environ Pathol Toxicol, 1979/7-1979/8;2(6):1235-45.
Tobin RB, Berdanier CD, Ecklund RE
PMID: 231081
Abstract
The effects of T4 and T3 upon ATPase activity of plasma membrane preparations produced by different methods has been studied. Media without Na+ or K+ was used to identify Mg++ activated ATPase, and media containing 100-120 mM Na+ and 20-30 mM K+ in addition to Mg++ was used to identify the augmented activity of Na-K ATPase. We also utilized media containing Na+, K+, and Mg++ in the presence and absence of ouabain to identify the Na+-K+ activation. We found no effect of doses of thyroxine in the physiologic range upon the Na+-K+ ATPase activity. A dose-response study indicated that high doses of T4 may stimulate Mg++ activated ATPase. In the P2 preparation of the Touster method we found minimally enhanced Na+-K+ ATPase activity. The quantity of T4 needed to cause such enhancement is approximately 50 times the physiologic replacement dose needed to restore thyroidectomized animals to a euthyroid state. We conclude that thyroid hormones do not stimulate Na+-K+ ATPase of plasma membranes when administered in a physiologic quantity, but may enhance Mg++ atpase activity when administered in a pharmacologic or toxic quantity.
MeSH terms
Adenosine Triphosphatases; Animals; Cell Membrane; In Vitro Techniques; Liver; Ouabain; Rats; Sodium-Potassium-Exchanging ATPase; Thyroidectomy; Thyroxine; Triiodothyronine
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