John M. Rumberger

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Normal serum can increase the rate of lipolysis in isolated adipocytes. Recently, we reported that the lipolytic effect of serum could be partly explained by effects of iron and transferrin. To further investigate these effects on fat cell metabolism, we have investigated effects of serum, iron, and transferrin on glucose transport in isolated rat(More)
Tumor necrosis factor-alpha (TNF-alpha) and hyperglycemia both impair insulin sensitivity in vivo. This may be secondary to stimulation of adipose tissue lipolysis and consequent increased circulating free fatty acids (FFAs). Here we report that neither TNF-alpha nor glucose alone has a pronounced effect on lipolysis in 3T3-L1 adipocytes. However, the(More)
Previous reports have demonstrated that normal serum can increase the rate of adipocyte lipolysis in vitro. However, the nature of the lipolytic activity has remained obscure. We have investigated the lipolytic activity of human serum using isolated rat adipocytes. Human serum resulted in a dose-dependent stimulation of lipolysis (glycerol release) in(More)
We determined the effect of butyrate and other short-chain fatty acids (SCFA) on rates of lipolysis in 3T3-L1 adipocytes. Prolonged treatment with butyrate (5 mM) increased the rate of lipolysis approximately 2-3-fold. Aminobutyric acid and acetate had little or no effect on lipolysis, however propionate stimulated lipolysis, suggesting that butyrate and(More)
Curcumin has been reported to inhibit insulin signaling and translocation of GLUT4 to the cell surface in 3T3-L1 adipocytes. We have investigated the effect of curcumin on insulin signaling in primary rat adipocytes. Curcumin (20 μM) inhibited both basal and insulin-stimulated glucose transport (2-deoxyglucose uptake), but had no effect on insulin(More)
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