| Summary: | Isolated fat cells were used for the study of in vitro effects of insulin on glucose metabolism in human and rat adipose tissue.In human subcutaneous fat cells, effects of insulin could be detected at concentrations of glucose in the medium from 1 to 10 μmoles/ml. Cellular responsiveness was inversely proportional to the glucose level. At a constant concentration of 6 μmoles of glucose per ml, the effects of insulin at various concentrations up to 500 μU/ml were investigated. At the highest concentration, which gave the maximal response, there was a 100% increase in the conversion of glucose-U-14C to glycerideglycerol and a 40% increase in glucose oxidation. The dose-response curve was steepest between 2 and 20 μU/ml.Rat epididymal fat cells were much more responsive to insulin. Glucose lipogenesis and pentose cycle activity could also be demonstrated in rat cells, whereas these activities could not be shown in fat cells from human omental and subcutaneous tissue. The findings for human cells are attributed to changes in cellular activity during preparation.
|
|---|