Erythrocyte sodium pump activity in human obesity.
In an attempt to resolve the prevailing confusion about erythrocyte sodium pump activity in obesity, we measured sodium-potassium-ATPase, ouabain-inhibitable (active) sodium efflux rate constant and intracellular sodium concentration in erythrocytes from 107 non-obese and obese subjects, with a body-mass index ranging from 17 to 54 kg X m-2. All the three independently measured variables were not significantly different between the two groups and no correlations were found between these three indices and body-mass index. The expression of ATPase activity in units of membrane protein allowed our previous data to be compared with this study and other reports. Our studies and most of the published reports suggest that there is no difference in erythrocyte sodium-potassium-ATPase and sodium transport between the vast majority of obese and non-obese subjects, but there is a subgroup of obese subjects (about 5%) with abnormally high erythrocyte sodium pump activity. The variable treatment of data from this subgroup and the small numbers of obese subjects studied by various investigators are largely responsible for the conflicting results about erythrocyte sodium pump activity.
D000328:Adult; D000368:Aged; D001693:Biological Transport, Active / Q000187:drug effects; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000097:blood*; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood
D007473:Ion Channels; D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase