OBJECTIVETo investigate the mechanism of hepatocytic insulin signal transduction defects in severely scalded rats, so as to clarify the molecular basis of postburn insulin resistance.

METHODSWistar rats inflicted by 30% III degree scalding on the back were employed as the model. The rat hepatocytic insulin receptor was partially purified by wheat-germ agglutinin (WGA)-sepharose 4B affinity chromatography. The change of receptor tyrosine protein kinase (TPK) activity, the receptor beta-subunit autophosphorylation and the hepatocytic insulin receptor binding behavior of scalded rats during early stage of scalding were observed by means of insulin receptor binding test, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) autoradiography of phosphorylation of insulin receptor and phosphorylation of exogenous substrate.

RESULTSThere exhibited no evident changes of hepatocytic insulin receptor maximal binding capacity and affinity at 3 postburn days (PBDs) in scalded rats. The autophosphorylation capacity of the receptor beta-subunit decreased significantly. And the receptor TPK activity decreased obviously and its reaction to insulin stimulation decreased markedly.

CONCLUSIONThe defects of the insulin receptor signal transduction in hepatocyte leading to the post-receptor defects of insulin biological effects might be molecular mechanism of postburn insulin resistance.