IGF-I contributes to glucose homeostasis in the Berlin Fat Mouse Inbred line.
This study aimed to investigate the tissue-specific role of the insulin-like growth factor 1 (IGF-I) on glucose homeostasis in the high-fatness selected Berlin Fat Mouse Inbred (BFMI) line. Therefore, the expression of different IGF-I transcripts and IGF-I protein, IGF-binding proteins, insulin as well as glucose tolerance was analyzed in BFMI in comparison with that in lean mice. In addition, dietary effects were investigated. The BFMI line showed normal blood glucose clearance on standard diet, but on high-fat diet the clearance was impaired, indicating the beginning of insulin resistance. Circulating IGF-I and insulin levels were elevated in BFMI than in lean mice on both diets along with a down-regulation of three IGF-I binding proteins in BFMI mice. Serum IGF-I levels corresponded with the expression pattern for both hepatic and one class II splice variants in reproductive adipose tissue, but not in muscle. High insulin and high IGF-I levels likely prevent BFMI mice from diabetes.
Department for Crop and Animal Sciences, Humboldt-Universität zu Berlin, Germany.
Nadine
N
Schäfer
Asja
A
Wagener
Claudia
C
Hantschel
Susanne
S
Mauel
Achim D
AD
Gruber
Gudrun A
GA
Brockmann
D000273:Adipose Tissue; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003920:Diabetes Mellitus / Q000503:physiopathology; D059305:Diet, High-Fat; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009765:Obesity / Q000097:blood / Q000235:genetics / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D018969:Insulin-Like Growth Factor Binding Proteins; C519530:insulin-like growth factor-1, mouse; D007334:Insulin-Like Growth Factor I; D005947:Glucose