INS and diabetes mellitus: In further support of an insulin-independent diabetic state in this model, we have demonstrated that HFHC/STZ guinea pigs not only respond clinically to a combination of metformin and glipizide with reversal of glucose intolerance, similar to a rat model, but also that this drug combination significantly improves survival without the need for exogenous insulin therapy, which is routinely required for survival in other rodent models with STZ-induced diabetes (Haughton et al., 1999; Reed et al., 2000).