The action of dibucaine in vitro on fat cell lipolysis and protein kinase activity.

Dibucaine at 0.1 and 0.25 mM markedly inhibited epinephrine-stimulated lipolysis in rat epididymal fat cells $\text{in}$$\text{vitro}$ but did not inhibit protein kinase activity. At 1.0 mM, dibucaine half-maximally stimulated protein kinase of fat cells under basal conditions but did not stimulate lipolysis. It is concluded that dibucaine inhibits lipolysis by a mechanism not involving inhibition of protein kinase.