K-p-nitrophenylphosphatase activity, Na and K content, Na permeability and membrane lipid composition in rabbit myocardium after cholesterol rich diet.
The aim of the present study was to investigate the effects of a cholesterol-rich diet on membrane function and lipid composition in rabbit myocardium. The activity and the ouabain sensitivity of the K-p-nitrophenylphosphatase (K-pNPPase), a partial reaction of the Na, K-ATPase, were diminished after a cholesterol/oil or pure cholesterol diet. The content of cholesterol, cholesterol esters and of several classes of phospholipids was enhanced in microsomes. A causal relationship is assumed between cholesterol accumulation and a decrease in membrane fluidity as well as in Na, K-ATPase activity. The intracellular Na content and the Na-Li-exchange rate were higher after the cholesterol diet. The increase in the Na content is supposed to be induced by a lower Na transport and a higher Na permeability. An enhanced Ca flux via the sarcolemma could be the consequence.
D009597:4-Nitrophenylphosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D002463:Cell Membrane Permeability; D002784:Cholesterol / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D008563:Membrane Lipids / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*
D002791:Cholesterol, Dietary; D008563:Membrane Lipids; D010743:Phospholipids; D010042:Ouabain; D002784:Cholesterol; D012964:Sodium; D010744:Phosphoric Monoester Hydrolases; D009597:4-Nitrophenylphosphatase; D011188:Potassium