In the first study, OMA treatment in Zucker fatty rats resulted in significantly lower systolic blood pressure compared to the placebo-treated group. OMA did not enhance basal or insulin-stimulated IRS-1 tyrosine phosphorylation or its association with PI3-kinase. Under basal and insulin-stimulated conditions, OMA treatment did not alter protein mass or phosphorylation of Akt/PKB, p42/44 ERK or AMPK, or total GLUT4 protein expression. These findings suggest that OMA's ability to improve insulin-stimulated muscle glucose uptake in Zucker fatty rats is not mediated by enhancing insulin or AMPK-signaling.In the second study, ATORVA treatment resulted in an improvement in whole body insulin sensitivity in both lean and fatty Zucker rats, and an increase in 2-deoxyglucose uptake by skeletal muscles (quadriceps and gastrocnemius) of the Zucker lean rats. Insulin-stimulated phosphorylation of Akt/PKB was significantly increased in skeletal muscle of ATORVA-treated lean and fatty rats. We conclude that ATORVA induces insulin sensitization in Zucker lean and fatty rats and this is associated with augmented insulin-dependent Akt/PKB phosphorylation.