Active Ca transport of sacroplasmic reticulum during experimental uremia. Changes in kinetics and lipid composition.
The Ca-transport system of sarcoplasmic vesicles of rabbits is altered by experimental uremia. 1. The influx rate constant of the experimental membranes decrease with a resulting decrease of the calcium influx rate. 2. The experimental membranes transport a smaller amount of Ca2+ per mol of ATP split than the controls, i.e. their transport ratio is discussed. 3. The calcium permeability of the experimental membranes increases with a resulting decreased concentrating ability. 4. The phosphatide content but not the cholesterol content of the experimental membranes decreases with a consequent increase of the cholesterol/phosphatide ratio. 5. The fatty acid pattern of total phosphatides of the experimental membranes changes. A relative decrease of palmitic acid and oleic acid occurs and a relative increase of stearic, arachidonic and higher unsaturated fatty acids. 6. The altered lipid composition of the membranes does not change the temperature dependence of the kinetics.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D004195:Disease Models, Animal; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D007700:Kinetics; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism; D009392:Nephrectomy; D010743:Phospholipids / Q000378:metabolism; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013696:Temperature; D014511:Uremia / Q000378:metabolism*
D005227:Fatty Acids; D010743:Phospholipids; D000251:Adenosine Triphosphatases; D002118:Calcium