CIRCULATING INSULIN-LIKE GROWTH-FACTOR-I CONCENTRATIONS IN CLINICALLYSEVERE OBESE PATIENTS WITH AND WITHOUT NIDDM IN RESPONSE TO WEIGHT-LOSS

Earlier studies have demonstrated decreased levels of circulating Insu lin-Like Growth Factor-I (IGF-I) in patients with NIDDM and IDDM (Yde 1969; Rieu and Binoux 1985), with a return to normal in those diabetic s who achieve improved metabolic control (Rieu and Binoux 1985; Ameil, Sherwin, Hintz, Gertner; Press and Tamborlane 1984) following insulin therapy. One method of improving metabolic control in clinically seve re obese NIDDM patients is the gastric bypass procedure (GBP). This st udy revealed a significant decrease in serum IGF-I concentrations in c linically severe obese patients with NIDDM (obese NIDDM) (105 ng/dl+/- 11; n = 29) as compared with clinically severe obese patients with nor mal glucose tolerances (obese control) (143+/-11; n = 21) and lean con trols (177+/-14; n = 19) (p < 0.001). Following a GBP, IGF-I levels in creased in the NIDDM group (142 ng/dl+/-13.0; n = 20) to the extent th at no significant difference was seen between postoperative NIDDM, obe se controls, and lean controls. Postoperative IGF-I levels in the obes e controls (151+/-14; n = 9) revealed no difference from preoperative levels. Postoperative obese NIDDM and obese control had a 28% and 29% decrease, respectively, in weight, with no difference between the grou ps in respect to Body Mass Indices. The NIDDM postoperative group reve aled reductions in levels of HbA(1)C, insulin, and glucose concurrent with elevations in IGF-I when compared with controls. We conclude that improvement in glucose control led to the increase in IGF-I levels.