Insulin-like growth factor binding protein-1 NIDDM: relationship with the insulin resistance syndrome

OBJECTIVE In order to examine the role of insulinlike growth factors in the pathogenesis of accelerated macrovascular disease in noninsulin-dependent diabetes mellitus (NIDDM), we investigated the relationship between the ins ulin resistance syndrome and the IGF axis, DESIGN Cross-sectional analysis of the relationship between insulin resista nce syndrome variables and concentrations of IGF-1, IGF-2, IGFBP-1 and IGFB P-3 in 80 subjects with NIDDM. RESULTS After correcting for age, sex and body mass index, concentrations o f IGFBP-1, correlated with those of HDL-cholesterol (r = 0.40; P < 0.001), triglycerides (r = -0.24; P = 0.04), insulin (r = -0.39; P < 0.001), intact proinsulin (r = -0.32; P = 0.006), des 31, 32 proinsulin (r = -0.40; P = 0 .001), and with insulin sensitivity (r = 0.38; P = 0.001) and PAI-1 activit y (r = -0.24; P = 0.05); IGF-1 levels only correlated with those of HDL-cho lesterol (r = -0.33; P = 0.005), and this was not explained by IGFBP-1 or i nsulin sensitivity. With additional correction for insulin, concentrations of IGFBP-1 still correlated with HDL-cholesterol (r = 0.40; P < 0.001), but not those of triglycerides or PAI-1 activity, There were no significant re lationships between levels of IGF-2 and any of the variables investigated, and IGFBP-3 levels only correlated with those of total cholesterol (r = 0,2 4, P = 0,04). CONCLUSIONS In NIDDM, concentrations of IGFBP-1 are related to those of ins ulin, insulin sensitivity, serum lipoproteins and PAI-1 activity, The relat ionship between concentrations of IGFBP-1 and HDL-cholesterol is not explai ned by insulin, Concentrations of IGF-1 are linked to HDL-cholesterol, and this is not explained by levels of IGFBP-1. IGFBP-1 concentrations were rel ated to PAI-1 activity, and this may be explained by insulin, which regulat es the production of IGFBP-1 and PAI-1.