Effects of puerarin, an active principle contained in the roots of Pueraria lobata (Leguminosae), on the regulation of glucose metabolism in an insulin deficient state were investigated in cultured myoblast C 2 C 12 cells using glucose uptake as indicator. Puerarin enhanced the uptake of radioactive glucose into C 2 C 12 cells in a concentration-dependent manner, which was abolished by prazosin pretreatment. Activation of alpha 1 -adrenoceptors by puerarin was further indicated by the displacement of [ 3H]prazosin binding in C 2 C 12 cells. The stimulatory action of puerarin on glucose uptake was also reduced in C 2 C 12 cells pre-incubated with the antagonists, both WB 4101 and RS 17 056, at concentrations sufficient to block alpha 1A -adrenoceptor (alpha 1A -AR). An activation of alpha 1A -AR seems responsible for the action of puerarin in C 2 C 12 cells. Pharmacological inhibition of phospholipase C (PLC) by U73312 resulted a concentration-dependent decrease of puerarin-stimulated glucose uptake in C 2 C 12 cells. This inhibition of glucose uptake by U73122 was specific because the inactive congener, U73343, failed to block puerarin-stimulated glucose uptake. Moreover, both chelerythrine and GF 109203X diminished the action of puerarin at concentration sufficient to inhibit protein kinase C (PKC). The obtained data suggest that an activation of alpha 1A -AR by puerarin in C 2 C 12 cells may increase the glucose uptake via the PLC-PKC pathway.