Glucose Homeostasis in the Nonobese Diabetic Mouse at the Prediabetic Stage

Because few data were available on glucose homeostasis at the early prediabetic stage in the nonobese diabetic (NOD) mouse, we investigated glycemia, insulinemia, and pancreatic insulin content under basal conditions in both sexes of 4-, 6-, and 8-week-old fed NOD mice, compared with sex- and age-matched fed C57BL/6 mice. We also investigated glucose tolerance in both sexes of fasting 8-week-old NOD and C57BL/6 mice. The main results obtained under basal fed conditions, when comparing both strains, were lower glycemia and higher insulinemia in NOD females at all ages investigated and in NOD males (particularly at 6 weeks of age). Glucose tolerance tests showed that: 1) the blood glucose response to 1 g/kg ip glucose was less sustained in both sexes of 8-week-old NOD mice than in their control counterparts; 2) the blood insulin response to glucose (1 g/kg ip) appeared earlier in both sexes of NOD mice than in sex-matched C57BL/6 mice; 3) an unusual sexual dimorphism existed in NOD mice, compared with contr...