IVGTT data of treated diabetic pigs showed that the area under the curve for serum HCP 20–90 min after intravenous glucose (AUC20–90HCP), an integrated measure of human insulin secretion by implanted hepatocytes, was 54% that of AUC20–90PCP (a comparable measure of endogenous insulin secretion from porcine pancreatic islets) of the same animals before induction of diabetes. This evidence concerns the gene INS and diabetes mellitus.