Association of serum levels of IGF-I and IGFBP-1 with renal function in patients with type 2 diabetes mellitus.
OBJECTIVE
Our aim was to determine whether serum Insulin-like growth factor-I (IGF-I) and Insulin-like growth factor binding protein-1 (IGFBP-1) levels were different between type 2 diabetic patients and non-diabetic control group. We also aimed to establish any relationship that might exist between the serum IGF-I and IGFBP-1 levels with the urinary albumin excretion (UAE), creatinine clearance and urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion (as a marker of renal tubular dysfunction) and other parameters (such as age, duration of diabetes, treatment, etc.) in patients with type 2 diabetes mellitus (DM).


METHODS
Fifty-nine type 2 diabetic patients and thirty-one non-diabetic controls were included in this study.


RESULTS
Mean serum IGF-I levels in diabetic patients were lower than the non-diabetic controls (158+/-12 vs. 287+/-26microg/l), (p<0.001). Serum IGFBP-1 levels were also higher in type 2 diabetic patients compared to the control group (67+/-5 vs. 35+/-4microg/l), (p<0.001). No relationship was obtained between IGF-I and IGFBP-1 levels with neither UAE nor urinary NAG excretion. A significant negative relationship was observed between creatinine clearance and serum IGFBP-1 level (r=-0.39, p=0.004). In multiple regression analysis IGF-I was independently and negatively associated with age and insulin treatment. On the other hand, IGFBP-1 was negatively related with creatinine clearance and positively related with the duration of diabetes.


CONCLUSIONS
These results suggest that type 2 DM leads to a decrease in the IGF-I while elevating the IGFBP-1 levels. Further studies are needed to clarify a potential role of increased levels of IGFBP-1 in decreased creatinine clearance in type 2 DM.
Akturk
Mujde
M
Department of Endocrinology, Gazi University, Faculty of Medicine, Ankara, Turkey. mujdeakturk@hotmail.com
Arslan
Metin
M
Altinova
Alev
A
Ozdemir
Aysegul
A
Ersoy
Reyhan
R
Yetkin
Ilhan
I
Ayvali
Elif
E
Gonen
Sevim
S
Toruner
Fusun
F
D000118:Acetylglucosaminidase / Q000652:urine; D003404:Creatinine / Q000652:urine*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged
D018970:Insulin-Like Growth Factor Binding Protein 1; D007334:Insulin-Like Growth Factor I; D003404:Creatinine; D000118:Acetylglucosaminidase