Interestingly, it has been demonstrated that whilst this strain does have reduced insulin secretion and impaired glucose tolerance in comparison to other strains of mice with higher expression levels of NNT, the C57BL/6J mice expressing the truncated protein have similar insulin secretion and glucose tolerance to the C57BL/6N mice expressing the full-length WT protein, though at lower levels than other strains (Wong et al. 2010). This evidence concerns the gene INS and Impaired glucose tolerance.