Phorbolesters enhance basal D-glucose transport but inhibit insulin stimulation of D-glucose transport and insulin binding in isolated rat adipocytes.

The C-kinase activating phorbolester TPA (12-O-Tetradecanoyl-beta-phorbol-13-acetate) and PdBu (4-beta-Phorbol-12,13,dibutyrate) stimulated D-glucose transport twofold in isolated rat adipocytes but inhibited high affinity insulin binding and the responsiveness of D-glucose transport to insulin stimulation by about 30%. Phorbolesters have therefore insulin-like effects but antagonize insulin on receptor and postreceptor level.