Objective: Adiponectin is the most abundant protein secreted by adipose tissue and is inversely associated with adiposity and insulin resistance. The aim of this study was to evaluate the hypothesis that marked weight loss, induced by gastric bypass surgery (GBS), would increase adiponectin gene expression in both upper and lower subcutaneous body fat and increase plasma adiponectin concentration.

Research methods and procedures: Adiponectin subcutaneous abdominal and femoral adipose tissue gene expression, determined by using quantitative reverse transcriptase-polymerase chain reaction, and adiponectin plasma concentrations, determined by using enzyme-linked immunosorbent assay, were evaluated in six extremely obese women (BMI = 57.1 +/- 4.1 kg/m²) before and 1 year after GBS.

Results: After GBS, subjects lost 36 +/- 5% of their initial body weight and showed increased insulin sensitivity, manifested by a marked decrease in homeostasis model assessment of insulin resistance from 10.7 +/- 4.1 to 1.4 +/- 0.3 (p < 0.05). Adiponectin gene expression increased 8- to 15-fold in subcutaneous abdominal and femoral adipose tissues (p < 0.05). Plasma adiponectin concentrations increased from 5.2 +/- 0.9 to 8.4 +/- 1.2 mug/mL (p < 0.05).

Discussion: These data show that marked weight loss induced by GBS increases adiponectin gene expression in both upper- and lower-body subcutaneous fat. The increase in adipose tissue adiponectin production resulted in an increase in plasma adiponectin concentrations, which likely contributed to the decrease in insulin resistance observed after weight loss.