Diabetes decreases Na+-K+ pump concentration in skeletal muscles, heart ventricular muscle, and peripheral nerves of rat.
Na+-K+-ATPase or the Na+-K+ pump is essential for some specific properties of muscle and nerve tissue such as contractility and excitability. Previous studies have shown conflicting variations in Na+-K+-ATPase activity or Na+-K+ pump concentration of muscle cells in experimental diabetes. Our study demonstrates that early untreated diabetes in rats induced by injection of streptozocin is associated with decreases in [3H]ouabain binding-site concentration of 24-48% in various skeletal muscles and 16% in peripheral nerves as well as a decrease in K+-dependent 3-O-methylfluorescein phosphatase activity of 21% in the heart ventricle. These effects could be prevented by insulin treatment. They probably represent a decrease in the concentration of Na+-K+ pumps. There was no evidence for more than one population of Na+-K+ pumps in intact samples of skeletal muscle and nerves from normal, diabetic, and insulin-treated animals. The decrease in Na+-K+ pump concentration in nerve cells may be due to atrophy of the axons. In skeletal muscles, myocardium, and peripheral nerves, the observed decrease in Na+-K+ pump concentration may be important for the pathophysiology of diabetes. We emphasize that quantification of Na+-K+-ATPase or the Na+-K+ pump in muscle and nerve tissue from diabetic animals should preferably be performed with either intact samples or crude homogenates of whole tissue.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism; D010525:Peripheral Nerves / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D001786:Blood Glucose; D010042:Ouabain; D012964:Sodium; C045349:3-O-methyl-fluorescein phosphatase; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium