To gain better insight into the insulin secretory activity of fetalbcells in response to glucose, the expression of glucose transporter 2 (GLUT-2), glucokinase and mitochondrial glycerol phosphate dehydrogenase (mGDH) were studied. Expression ofGLUT-2mRNA and protein in pancreatic islets and liver was signi®cantly lower in fetal and suckling rats than in adult rats.