Insulin-resistant Na+ pump activity in adipocytes from obese humans
Mott, D.M.; Clark, R.L.; Andrews, W.J.; Foley, J.E.
American Journal of Physiology 249(2 Pt 1): E160-E164
1985
ISSN/ISBN: 0002-9513 PMID: 2411146 Document Number: 254884
Basal and maximum insulin-stimulated sodium+-pump activity was estimated in adipocytes from persons with normal glucose tolerance over a range of body mass indexes (BMI). In a comparison of 13 lean (BMI less than 25) and 15 obese (BMI over 40) persons basal activities per unit surface area were similar, but the maximum insulin-stimulated activity was significantly reduced in the obese group. The mean percentage insulin stimulation of the Na+ pump above basal activity was 48 +or- 7 for the lean and 14 +or- 2 for the obese group. A similar relation was observed in these subjects for glucose transport where basal activities per unit surface area again were similar but the maximum insulin-stimulated transport was reduced in the obese subjects. The results indicate that changes in Na+-pump activity may be a manifestation of the insulin-resistant state that could contribute to the development of obesity as a result of decreased cellular thermogenesis.