Changes in adipokine expression during food deprivation in the mouse and the relationship to fasting-induced insulin resistance.

We investigated the changes in insulin resistance and adipose tissue expression of the adipokines resistin, adiponectin, and leptin and the transcription factors peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and retinoid X receptor-alpha (RXR-alpha) during 48 h of food deprivation. Insulin sensitivity (SI) declined, whereas glucose effectiveness (SG) increased. Plasma adiponectin levels declined in the first 8 h and remained constant thereafter. There was no correlation between either SI or SG and adiponectin protein or mRNA levels. PPAR-gamma mRNA abundance remained constant, whereas leptin and resistin mRNAs and plasma leptin declined and RXR-alpha mRNA abundance increased in both white and brown fat. Leptin mRNA abundance was closely correlated with SI (R2 = 0.91 and 0.87 for white and brown fat, respectively). Resistin mRNA abundance correlated inversely with SG (R2 = 0.99 and 0.84 for white and brown fat, respectively). These data indicate that changes in the expression of leptin are more closely correlated with the insulin resistance of fasting than with changes in other adipokines or RXR-alpha and PPAR-gamma expression.