Early effects of streptozotocin-induced diabetes on insulin-like growth factor-I in the kidneys of growth hormone-transgenic and growth hormone-deficient dwarf mice.
BACKGROUND
The renal growth and hyperfiltration observed in humans and animals with early diabetes might be dependent on growth hormone (GH) and insulin-like growth factor (IGF)-I. The aim of this study was to investigate the early changes in kidney IGF-I in experimental diabetes in mice transgenic for bovine GH and in genetically GH-deficient Ames dwarf mice.


METHODS
At 2, 4 and 8 days after a single intraperitoneal injection with streptozotocin, animals were weighted, bled and killed; plasma was analyzed for glucose and IGF-I. IGF-I levels were determined in tissue from snap-frozen kidney and liver.


RESULTS
Body weight decreased significantly after the induction of diabetes. Kidney weight increased significantly in GH-transgenic, but not in normal or dwarf mice. Plasma IGF-I was significantly decreased at day 2 in GH-transgenic and normal mice, while liver IGF-I was increased at day 4 in all mice. Kidney IGF-I increased significantly in normal and GH-transgenic mice and was increased more than 3-fold at day 4 in GH-transgenic mice. In dwarf mice, no kidney IGF-I was detectable.


CONCLUSIONS
The diabetes-induced increase in renal IGF-I is dependent on the presence of GH. GH deficiency may protect diabetic animals from early changes in the kidney.
Jacobs
M L
ML
Department of Internal Medicine, University of Dijkzigt, Rotterdam, The Netherlands.
Chandrashekar
V
V
Bartke
A
A
Weber
R F
RF
D000375:Aging / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000503:physiopathology*; D004392:Dwarfism / Q000235:genetics*; D013006:Growth Hormone / Q000096:biosynthesis* / Q000172:deficiency* / Q000235:genetics; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000096:biosynthesis* / Q000378:metabolism; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology; D008099:Liver / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000096:biosynthesis / Q000235:genetics; D011401:Promoter Regions, Genetic; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis
D001786:Blood Glucose; D011993:Recombinant Fusion Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D010729:Phosphoenolpyruvate Carboxykinase (GTP)