title: Diabetic modifier QTL, Dbm4, affecting elevated fasting blood glucose concentrations in congenic mice.
abstract: We have previously identified four significant quantitative trait loci (QTL) affecting plasma glucose concentrations on F(2) progeny of hypoinsulinemic diabetic Akita mice, heterozygous for the Ins2 gene Cys96Tyr mutation, and non-diabetic A/J mice, one of which on chromosome 15 named Dbm4 (diabetic modifier QTL 4) was shown to affect fasting plasma glucose concentrations with a maximum LOD score of 6.17. To estimate the influence of Dbm4 itself to the diabetes-related phenotypes, we constructed congenic strain with heterozygous Ins2 mutation using the Akita allele as donor of Dbm4 locus in the A/J genetic background, and measured quantitative traits including plasma glucose concentrations in glucose tolerance test (GTT). In this study, we found the Akita allele in Dbm4 was associated with higher fasting plasma glucose concentrations as in previous QTL analysis. According to gene expression assay, key enzymes of hepatic gluconeogenesis were expressed to the more increased degree in the liver of congenic mice compared to the A/J allele based control mice. Based on these results, we concluded that diabetic modifier gene(s) exist on Dbm4 locus affecting fasting plasma glucose concentrations via regulation of gluconeogenic gene expression in the hypoinsulinemic diabetic condition. Identification of the modifier gene responsible for Dbm4 would provide new drug development targets for human type 2 diabetes with hepatic insulin resistance.
authors: Department of Metabolic Diseases, Pharmacology Research Labs., Astellas Pharma Inc., 21 Miyukigaoka,Tsukuba, Ibaraki 305-8585, Japan.
authors: Shigeru
authors: S
authors: Takeshita
authors: Susumu
authors: S
authors: Kitayama
authors: Takao
authors: T
authors: Suzuki
authors: Maki
authors: M
authors: Moritani
authors: Hiroshi
authors: H
authors: Inoue
authors: Mitsuo
authors: M
authors: Itakura
mesh_terms: D000818:Animals; D001786:Blood Glucose; D001835:Body Weight; D002874:Chromosome Mapping; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000235:genetics; D004195:Disease Models, Animal; D005215:Fasting; D056726:Genetic Association Studies; D008040:Genetic Linkage; D005943:Gluconeogenesis / Q000235:genetics; D008126:Lod Score; D008297:Male; D051379:Mice; D020297:Mice, Congenic; D008822:Mice, Transgenic; D040641:Quantitative Trait Loci
chemical_list: D001786:Blood Glucose