Glucose-dependent insulinotropic polypeptide effects in type 1 diabetes

Glucose-dependent insulinotropic polypeptide (GIP) has been proposed to exert insulin-independent effects on lipid and bone metabolism. We investigated the effect of a 6-day s.c. GIP infusion on circulating lipids, white adipose tissue (WAT), brown adipose tissue (BAT), hepatic fat content, and inflammatory markers in patients with type 1 diabetes. In a randomized, placebo-controlled, double-blind, crossover study, 20 men with type 1 diabetes underwent a 6-day continuous s.c. infusion with GIP (6 pmol/kg/min) and placebo (saline), with an interposed seven-day washout period. Each intervention period involved three study days: Day 0 (baseline measurements, a baseline abdominal adipose tissue biopsy and blood sampling), Day 1 (fasting blood sample after 24 hours infusion), and Day 6 (fasting blood sample, an abdominal adipose tissue biopsy).