Acridine orange, an inhibitor of protein kinase C, abolishes insulin and growth hormone stimulation of lipogenesis in rat adipocytes.

To determine whether protein kinase C plays a role in the actions of insulin and growth hormone in rat adipocytes, we tested the effect of acridine orange, a potent inhibitor of kinase C, on the lipogenic activity of both hormones. This compound completely inhibited the effects of insulin, growth hormone and phorbol ester 12-myristate 13-acetate, whereas 9-acridine carboxylic acid, an analog of acridine orange which does not inhibit kinase C, had no effect. Acridine orange did not act through inhibition of hormone binding. These data are consistent with the involvement of kinase C in the action of insulin and growth hormone on lipogenesis in rat fat cells.