T1D and T2D are characterized by hyperglycemia and insulin resistance (IR), but in T1D the IR occurs even in the absence of metabolic syndrome features. The loss of β-cell insulin secretion in T1D results in lower portal and thus hepatic insulin concentrations in T1D than in T2D or nondiabetic (non-DM) individuals, affecting the GH-IGF axis, as exogenous insulin is subcutaneously delivered in T1D. In this study, we examined how the GH-IGF axis differs by diabetes type, and how it relates to IR. This study included youth (mean age 15±2 years, 37% female) with T1D (n=16), T2D (n=27) and non-DM controls (n=38). A morning fasting blood sample was obtained to measure GH, IGF-1, and IGF binding proteins (IGF BP-1, 2 and 3). Hyperinsulinemic euglycemic clamps were performed to measure glucose infusion rate (GIR), an estimate of skeletal muscle IR, and serum free fatty acid (FFA) suppression. GH, IGF BP-1 and IGF BP-2 were higher in T1D compared to non-DM youth (Figure). Higher IGF BP-3 was associated with lower GIR (more muscle IR) in all youth, but lower IGF BP-1 and 2 were associated with lower GIR in non-DM youth only. Higher GH, IGF BP-1 and IGF BP-3 were associated with less FFA suppression (more adipose IR) in T1D youth only. The GH-IGF-1 axis is altered and is differentially correlated to IR in T1D versus T2D. These data provide clues regarding the unique phenotype of IR in T1D.
J.K. Snell-Bergeon: None. J.E.B. Reusch: Board Member; Self; American Diabetes Association. Other Relationship; Self; Merck & Co., Inc. A.D. Baumgartner: None. M. Cree-Green: None. K.J. Nadeau: None.
American Diabetes Association (7-13-CD-10 to J.K.S-B.)