Changes in Free Insulin-Like Growth Factor-1 and Leptin Concentrations during Acute Metabolic Decompensation in Insulin Withdrawn Patients with Type 1 Diabetes

To determine the effect of acute insulin withdrawal and its subsequent replacement on components of the insulin-like growth factor (IGF)-1 binding protein system and on circulating leptin levels in patients with type 1 diabetes. Seventeen patients (age 31 yr ± 10) with type 1 diabetes treated with continuous subcutaneous insulin infusion (HbA1c 7.6% ± 1.0) were studied. The protocol consisted of two phases: acute insulin withdrawal of up to 8 h followed by a further 2-h period of insulin replacement. For the first phase the basal insulin infusion was stopped (at 0300 h), and for the second a single dose of either regular human or insulin lispro was given subcutaneously (0.2 U/kg). Plasma insulin, glucose, growth hormone, glucagon, IGF-1, free IGF-1, IGFBP-1, -2, -3 and leptin were measured. Results: After interruption of the basal insulin infusion, plasma free insulin levels fell from 60 ± 12.0 pmol/L to 10.8 ± 4.2 pmol/L, and plasma glucose rose from 5.6 ± 0.4 mmol/L to 14.8 ± 1.2 mmol/L (P < 0.01). Duri...