Insulin-like growth factor-I and insulin-like growth factor binding protein-1 in a representative population of type 2 diabetic patients in Sweden.

OBJECTIVE: To study the influence of type 2 diabetes on the insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-1 (IGFBP-1) serum levels in an area-based population of type 2 patients previously described. RESULTS: The patients (n = 151) were elderly (70.6 +/- 0.7 years of age) and moderately overweight (BMI 27.0 +/- 0.4 kg/m2). Most patients (83%) were treated with either diet alone or diet in combination with sulphonylurea. Metabolic control measured as HbAlc deteriorated with duration (p < 0.001) and between groups treated with diet (HbA1c 5.8 +/- 0.6), sulphonylurea (7.5 +/- 0.2) and insulin (7.7 +/- 0.4). Mean levels of IGF-I were within reported normal range, but were lower in the insulin-treated as compared to the non-insulin-treated patients. Levels of IGF-I decreased with diabetes duration and with increased blood glucose. There was a positive correlation between IGF-I and insulin levels and also an inverse correlation between IGF-I and IGFBP-1 levels. The IGFBP-1 levels were twofold higher than reported in non-diabetic individuals. In multiple stepwise correlation analysis, 37% of the variability in IGFBP-1 could be explained by BMI, IGF-I SD score, age, IGF-I, and fasting blood glucose. CONCLUSION: Our study indicates that influence of type 2 diabetes on IGF-I bioavailability in individual patients is modulated by insulin, body weight (presumably reflecting insulin sensitivity) and metabolic control. Furthermore, increased levels of IGFBP-1 are strongly associated with decreased b-cell function in type 2 diabetes mellitus.

Absorption of rapid-acting insulin in obese and nonobese NIDDM patients.

OBJECTIVE: To study the absorption rate of rapid-acting insulin from subcutaneous injection sites in nonobese and obese non-insulin-dependent diabetes mellitus (NIDDM) patients. RESEARCH DESIGN AND METHODS: Ten nonobese and 10 obese NIDDM patients (body mass indexes 24.1 +/- 0.4 and 31.4 +/- 0.8 kg/m2, respectively) received four subcutaneous injections of 125I-labeled rapid-acting insulin (Actrapid Human, 5 U): three in the abdominal wall above, lateral to, and below the umbilicus; and one in the thigh. The depth of the subcutaneous fat layer was measured using ultrasound techniques. The residual radioactivity was monitored externally for 270 min. RESULTS: The disappearance half-life of 125I-insulin was between 4 and 6 h from all injection sites, with the exception of the upper abdominal area in the nonobese subjects, where it measured approximately 3 h. The residual radioactivity did not differ between nonobese and obese patients measured from any of the sites. In the nonobese group, the most rapid absorption of 125I-insulin was found from the upper abdominal area and the slowest from the thigh. In the obese group, the absorption rates did not differ between sites. No correlation was found between the depth of the fat layer and the residual radioactivity when measured at any site. CONCLUSIONS: Our results indicate that the absorption of rapid-acting insulin is markedly slow in both obese and nonobese NIDDM patients compared with IDDM patients and healthy subjects studied previously. In the nonobese group, the most rapid absorption of 125I-insulin is obtained after injection into the upper abdominal area. Inter- and intraregional differences are small in the obese patients. Consequently the choice of injection site is of little importance in this group.