Endocrine Abstracts

In recent years there has been considerable progress in identifying how insulin signals to the cell's interior. The interaction of insulin with its receptor triggers the formation of phosphatidyl inositol (3, 4, 5) trisphosphate (PIP3) at the plasma membrane which then activates several signal transduction pathways. Perhaps the most important of these is the protein kinase cascade in which 3-phosphoinositide-dependent protein kinase-1 (PDK1) activates protein kinase B (PKB, al...

A number of growth factors and their receptor signalling pathways are expressed in the embryonic and adult pancreas. Recent evidence from studies using murine gene-targeting strategies has implicated insulin and IGF-1 receptor and post-receptor signalling pathways in beta cell function. A number of roles for these signalling mechanisms have been reported in both beta cell development and survival and in regulating insulin gene expression and insulin secretion. Global and condi...

Receptors for insulin and insulin-like growth factor I (IGF-I) have been identified in endothelial cells derived from micro- and macrovessels. The insulin receptor in endothelial cells is structurally similar to that in other cell types and activation of its receptor tyrosine kinase leads to phosphorylation of insulin receptor substrate-1. In endothelial cells, insulin mediated activation of phosphatidylinositol 3-kinase (PI3K), Akt (protein kinase B)and the mitogen-activated ...

The ovary may not be an obvious target tissue for insulin action but there is ample evidence to suggest that insulin affects glucose metabolism, steroidogenesis and cell growth/differentiation, and that these effects are relevant to both normal ovarian physiology and to disorders of ovarian function. Glucose uptake and glycolysis by granulosa cells - important for providing energy for the maturing oocyte are regulated by both insulin and gonadotrophins. In the human ovary, ins...