Restoration of Adiponectin Pulsatility in Severely Obese Subjects After Weight Loss

Abstract

Diurnal variations of adiponectin levels have been studied in normal-weight men and in diabetic and nondiabetic obese subjects, but no data have been reported in obese subjects after weight loss. We collected blood samples at 1-h intervals over 24 h from seven severely obese subjects before and after massive weight loss consequent to surgical operation (bilio-pancreatic diversion [BPD]) to measure adiponectin, insulin, glucose, and cortisol levels. Insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp (M value). Studies of diurnal variations and pulsatility of adiponectin, insulin, and cortisol were performed. The pulsatility index (PI) of adiponectin increased after BPD from 0.04 to 0.11 μg/min (P = 0.01). Insulin PI significantly increased after the operation (1.50 vs. 1.08 pmol · l^–1 · min^–1, P = 0.01), while cortisol PI did not significantly change. The adiponectin clearance rate changed from 0.001 ± 10⁻⁴ · min⁻¹ before BPD to 0.004 ± 8 · 10⁻⁴ · min⁻¹ after BPD (P = 0.03). Insulin clearance increased from 0.006 ± 6 · 10⁻⁴ · min⁻¹ before BPD to 0.009 ± 4 · 10⁻⁴ · min⁻¹ after BPD (P = 0.02). The M value doubled after surgery (27.08 ± 8.5 vs. 53.34 ± 9.3 μmol · kg_FFM⁻¹ · min⁻¹; P < 0.001) becoming similar to the values currently reported for normal-weight subjects. In conclusion, in formerly severely obese subjects, weight loss paired with the reversibility of insulin resistance restores homeostatic control of the adiponectin secretion, contributing to the reduction of cardiovascular risk already described in these patients.