Insulinotropin PACAP potentiates insulin-stimulated glucose uptake in 3T3 L1 cells.
Pituitary adenylate cyclase-activating polypeptide (PACAP) is localized in pancreatic nerve fibers and islets and potently augments glucose-induced insulin secretion. The present study explored a possible extra-pancreatic action of PACAP. The specific PACAP receptor (PAC1 receptor) was expressed in the rat fat tissue and 3T3-LI adipocytes. PACAP-38 (10 nM) significantly enhanced insulin-induced 2-deoxyglucose uptake by 3T3-L1 adipocytes. Insulin-stimulated phosphatidylinositol 3-kinase activity was further increased by PACAP-38, whereas the tyrosine-phosphorylation of insulin receptor beta-subunit and insulin receptor substrate-1 was unaltered by PACAP-38. These results reveal that PACAP-38 enhances insulin-induced glucose uptake, an effect probably mediated by insulin-stimulated phosphatidyl-inositol 3-kinase, and that PACAP potentiates not only insulin secretion, but also insulin action in adipocytes.
Nakata
M
M
Department of Physiology, Faculty of Medicine, Kagoshima University, Japan.
Shioda
S
S
Oka
Y
Y
Maruyama
I
I
Yada
T
T
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation; D005947:Glucose / Q000378:metabolism*; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D055504:Insulin Receptor Substrate Proteins; D051379:Mice; D008969:Molecular Sequence Data; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats
D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; C526296:Irs1 protein, rat; D010750:Phosphoproteins; D019869:Phosphatidylinositol 3-Kinases; D005947:Glucose