The influence of sub-optimal protein nutrition on insulin hypersecretion evoked by high-energy/high-fat feeding in rats.

Low (8%) protein feeding during pregnancy impairs the functional development of the fetal endocrine pancreas. Continued low-protein feeding post-natally decreases pancreatic insulin content and secretion, whereas transfer to standard diet evoked beta-cell recuperation. Glucose-stimulated insulin secretion (GSIS) and insulin action were examined in vivo at 28 days after transfer from 8% protein diet to a high-energy/high-fat/standard (20%)-protein diet (HEF diet). HEF feeding dramatically enhanced GSIS after intravenous glucose in control rats, but not in rats previously maintained on the low-protein diet. However, glucose disappearance after intravenous glucose, and glucose production and whole-body glucose disposal during euglycaemic-hyperinsulinaemic clamps were unaffected by prior protein malnutrition. In conclusion, impaired insulin secretion after protein malnutrition is exacerbated by high-energy/high-fat feeding, but this response is not linked to enhanced whole-body insulin resistance.