Regulation of protein kinase B and glycogen synthase kinase-3 by insulin and beta-adrenergic agonists in rat epididymal fat cells. Activation of protein kinase B by wortmannin-sensitive and -insensitive mechanisms.

Previous studies using L6 myotubes have suggested that glycogen synthase kinase-3 (GSK-3) is phosphorylated and inactivated in response to insulin by protein kinase B (PKB, also known as Akt or RAC) (Cross, D. A. E.

The hormonal regulation of pyruvate dehydrogenase complex.

The pyruvate dehydrogenase complex has a central role in the regulation of mammalian metabolism as it represents the point-of-no-return in the utilization of carbohydrate. This article summarizes our studies into how signalling systems initiated by hormones binding to cell surface receptors can reach the pyruvate dehydrogenase system which is located within the inner mitochondrial membrane. One class of hormones which activate pyruvate dehydrogenase are those that increase cytoplasmic Ca2+.

Multiple signalling pathways involved in the stimulation of fatty acid and glycogen synthesis by insulin in rat epididymal fat cells.

We have investigated the signalling pathways involved in the stimulation of glycogen and fatty acid synthesis by insulin in rat fat cells using wortmannin, an inhibitor of phosphatidylinositol 3-kinase, and rapamycin, which blocks activation of p70 ribosomal S6 protein kinase (p70S6K). Insulin produced a decrease in the activity of glycogen synthase kinase-3 which is likely to be important in the observed stimulation of glycogen synthase. Both of these actions were found to be sensitive to inhibition by wortmannin.