Genetic and genomic studies of the BTBR ob/ob mouse model of type 2 diabetes.
The BTBR mouse strain harbors alleles promoting insulin resistance. When made genetically obese (ob/ob), these mice develop severe type 2 diabetes (fasting glucose >400 mg/dL). By contrast, C57BL/6 ob/ob mice are able to compensate for the obesity-induced insulin resistance by increasing pancreatic insulin secretion and thus maintain only slightly elevated plasma glucose levels (<250 mg/dL). Islet insulin secretory responses to glucose are undiminished in the remaining islets of BTBR ob/ob mice. A genome-wide linkage analysis identified 3 major loci influencing plasma glucose and/or insulin levels in an F2ob/ob sample derived from the 2 strains. A locus on chromosome 2 affects insulin sensitivity and is independent of obesity. Loci on chromosomes 16 and 19 affect fasting glucose and insulin levels and likely affect beta-cell mass or function. Analysis of mRNA expression patterns revealed a reduction in lipogenic gene expression in adipose tissue associated with obesity. Conversely, hepatic lipogenic gene expression increases in obese mice, but to a much greater extent in the diabetes-resistant C57BL/6 strain. We propose that hepatic lipogenic capacity affects susceptibility to obesity-induced diabetes.
Clee
Susanne M
SM
Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
Nadler
Samuel T
ST
Attie
Alan D
AD
D000818:Animals; D002874:Chromosome Mapping; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology / Q000235:genetics*; D004195:Disease Models, Animal; D005260:Female; D007333:Insulin Resistance / Q000235:genetics*; D008297:Male; D051379:Mice; D008820:Mice, Obese; D009765:Obesity / Q000150:complications