OBJECTIVETo determine the molecular mechanisms linking intrauterine growth restriction (IUGR) to adult type 2 diabetes mellitus, the effect of IUGR on the hepatic post-receptor insulin-signaling pathway was investigated in the adult offspring.

METHODSThe IUGR model was prepared by maternal protein-malnutrition. Western blotting analysis was undertaken to assess hepatic expression of insulin receptor substrate (IRS-2), phosphoinositol 3-kinase (PI-3K), protein kinase B (PKB), phosphorylated PKB-Ser473 and glycogen synthase kinase (GSK) 3 in 8-week-old male IUGR rats.

RESULTSThe basal levels of PI-3K protein decreased in IUGR rats compared with normal controls (p<0.01), whereas GSK-3beta protein level significantly increased in IUGR rats (p<0.01). Both PKB and phosphorylated PKB-Ser473 protein levels significantly decreased in the liver of IUGR rats compared with normal controls (p<0.01)). After insulin administration, phosphorylated PKB-Ser473 significantly increased to 182% of basal level in control rats(p<0.01); However, phosphorylation of PKB which responded to insulin was markedly blunted in IUGR rats compared with controls and only increased to 123% of basal level (p<0.05).

CONCLUSIONSThe level of PI-3K and PKB and phosphorylated PKB-Ser473 expression decreased in the liver of IUGR rats, whereas the levels of GSK-3beta protein increased. It may contribute to the pathogenesis of insulin resistance in the IUGR rats.