Diabetes, Vol 49, Issue 9 1590-1596, Copyright © 2000 by American Diabetes Association
Type 2 diabetes-like hyperglycemia in a backcross model of NZO and SJL mice: characterization of a susceptibility locus on chromosome 4 and its relation with obesity
L Plum, R Kluge, K Giesen, J Altmuller, JR Ortlepp and HG Joost
Institute of Pharmacology and Toxicology, Medical Faculty of the Technical University Aachen, Germany.
A backcross model of New Zealand obese mice (NZO) with the lean,
atherosclerosis-resistant SJL strain was established to locate genes
responsible for obesity, insulin resistance, and type 2 diabetes-like
hyperglycemia. In male NZO x F1 backcross mice, a major susceptibility
locus for the development of hyperglycemia and hypoinsulinemia (Nidd/SJL)
was identified on chromosome 4 between the markers D4Mit278 and D4Mit232,
10-28 cM distal of the previously described Nidd1 locus. The diabetogenic
allele has presumably been contributed by the SJL genome, and it appeared
to be responsible for approximately 60% of the total prevalence of
hyperglycemia. The presence of Nidd/SJL did not alter body weight or weight
gain by week 12. Thereafter, it was associated with reduced weight gain or
weight loss, presumably as a consequence of decompensated hyperglycemia. In
all male backcross mice, the prevalence of hyperglycemia at week 22
increased with the body weight at week 12, suggesting that the development
of hyperglycemia was dependent on the degree of obesity. In the absence of
Nidd/SJL, mice weighing <50 g at week 12 did not develop hyperglycemia
by week 22. In contrast, in animals carrying the diabetogenic allele, the
prevalence of hyperglycemia was 20 and 64% when the 12-week weight was
<45 and 45-50 g, respectively. These data are consistent with the
conclusion that Nidd/SJL represents a diabetes gene that lowers the obesity
threshold for the development of hyperglycemia and hypoinsulinemia.