Many of our customers use C57BL/6J (B6, 000664) mice as normoglycemic and glucose tolerant controls for certain obesity/diabesity and genetically engineered mouse mutants with a B6 background. Glucose intolerance is a relative term: due to diminished glucose-stimulated insulin secretion, B6 clearance rates for injected glucose are slower than for some inbred strains such as C3H/HeJ (Goren et al. 2004, Freeman et al. 2006).
However, B6 males are very insulin sensitive and, following a glucose injection, restore their glucose levels to within a normal range over a two-hour period. B6 mice clear glucose much faster than do males from truly glucose-intolerant strains, such as KK/HlJ (002106), NZO/HlLtJ (002105), and NON/LtJ (002423), the latter reportedly expressing the wild-type Nnt allele (online supplement to Freeman et al. 2006).
The Mouse Phenome Database indicates that though plasma glucose levels in B6 mice before and after being fed a high-fat diet are higher than those in many other comparably fed inbred strains, they are within the normal range for inbred strains.
References
Freeman HC, Hugill A, Dear NT, Ashcroft FM, Cox RD. 2006. Deletion of nicotinamide nucleotide transhydrogenase: a new quantitative trait locus accounting for glucose intolerance in C57BL/6J mice. Diabetes 55:2153-6.
Goren JH, Kulkarni RN, Kahn CR. 2004. Glucose Homeostasis and Tissue Transcript Content of Insulin Signaling Intermediates in Four Inbred Strains of Mice: C57BL/6, C57BLKS/6, DBA/2, and 129X1. Endocrinology 145:3307-23