SERUM INSULIN-LIKE GROWTH-FACTOR-II LEVELS IN NORMAL ADOLESCENTS AND THOSE WITH INSULIN-DEPENDENT DIABETES-MELLITUS

OBJECTIVE Unlike IGF-I and its principal binding proteins, data regard ing IGF-II levels have not been well defined in normal subjects and th ose with insulin-dependent diabetes mellitus (IDDM). We have therefore measured IGF-II, as well as IGF-I, and IGFBP-3, levels in a large coh ort of subjects with IDDM and in age/sex matched controls. PATIENTS On e hundred and fourteen patients with IDDM (57 males, 57 females) and 8 9 control subjects (49 males, 40 females). MEASUREMENTS Random blood s amples were obtained from each subject for the measurement of IGF-II, IGF-I and IGFBP-3 levels. RESULTS Mean values of IGF-II (+/-SEM) were 630 (+/-27.8) mu g/l and 646 (+/-32.3) mu g/l in female and male contr ols, compared to 569 (+/-23.3) mu g/l and 623.3 (+/-28.1) mu g/l in fe male and male diabetics respectively. IGF-II levels did not differ sig nificantly between the sexes or show any change with transition throug h puberty in either control or diabetic groups. In contrast, IGF-I lev els increased through puberty peaking at stages 3-5 in controls (P<0.0 01) and G4-5 (P=0.002) in diabetic males but not females. IGF-I levels in all diabetics were generally lower than in controls, differences r eaching significance at G4-5 in males (P=0.002) and B5 in females (P=0 .002). IGFBP-3 levels did not show any variation with puberty stage in diabetics, in contrast to controls where levels increased, peaking at G4-5 in males (P=0.001) and B3 in females. IGFBP-3 levels were lower in diabetics of both sexes and at all stages compared to controls (P r ange 0.047 to <0.001). Multiple regression analysis revealed significa nt correlations between IGF-II and IGFBP-3 (F=20.1, P=<0.001) and reaf firmed previously observed associations for IGF-I and IGFBP-3, The sum of IGF-I and IGF-II (expressed as nmol/l) correlated with IGFBP-3; r= 047 in controls and 0.60 in diabetics. CONCLUSIONS Insulin-dependent d iabetes mellitus is not associated with any significant changes in IGF -II levels during puberty. The binding of IGFBP-3 for both IGF-I and I GF-II is unaltered by insulin-dependent diabetes mellitus.