Dose-dependent effects of recombinant human insulin-like growth factor (IGF)-I/IGF binding protein-3 complex on overnight growth hormone secretion and insulin sensitivity in type 1 diabetes

Tero Saukkonen, Rakesh Amin, Rachel M. Williams, Charles Fox, Kevin C. Yuen, Martin A. White, A. Margot Umpleby, Carlo L. Acerini, David B. Dunger

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52 Scopus citations

Abstract

GH hypersecretion in type 1 diabetes has been implicated in the pathogenesis of insulin resistance, and microangiopathic complications, and may result from reduced circulating IGF levels. We examined the effects of recombinant human (rh)IGF-I [complexed in equimolar ratio with rhIGF binding protein (BP)-3 (rhIGF-I/IGFBP-3)] replacement on overnight GH levels and insulin sensitivity in type 1 diabetes. Fifteen subjects, 13-24 yr old (10 male), were given rhIGF-I/IGFBP-3 or placebo as a daily sc injection for 2 d. After the second injection overnight, insulin requirements for euglycemia were determined (0400-0800 h), followed by a 4-h, two-step (insulin, 0.6 and 1.5 mU/kg·min) hyperinsulinemic euglycemic [90 mg/dl (5 mmol/liter)] clamp. In each subject, the protocol was repeated on three occasions in random order. Seven subjects received placebo and rhIGF-I/IGFBP-3 (0.1 mg/kg·d and 0.4 mg/kg·d), and eight subjects received placebo and rhIGF-I/IGFBP-3 (0.2 mg/kg·d and 0.8 mg/kg·d). We found dose-dependent increases in circulating IGF-I and IGFBP-3 concentrations after rhIGF-I/IGFBP-3. These were paralleled by significant reductions in mean overnight GH levels and GH pulse amplitude. We also observed dose-dependent effects of rhIGF-I/IGFBP-3 on overnight insulin requirements for euglycemia, with reductions of up to 41%. Insulin sensitivity, defined by M-values, was improved with rhIGF-I/IGFBP-3 (0.4 and 0.8 mg/kg·d). Thus, restoration of circulating IGF-I and IGFBP-3 levels with rhIGF-I/IGFBP-3 suppresses GH secretion in adolescents with type 1 diabetes, leading to reduced insulin requirements and improvements in insulin sensitivity.

Original languageEnglish (US)
Pages (from-to)4634-4641
Number of pages8
JournalJournal of Clinical Endocrinology and Metabolism
Volume89
Issue number9
DOIs
Publication statusPublished - Sep 2004
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism

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