Endocrine Abstracts

Introduction. Adiponectin is a novel circulating adipocyte derived protein, whose plasma concentrations paradoxically decrease with increasing fat mass. Adiponectin has been shown to improve both glucose and lipid metabolism, and circulating concentrations are inversely correlated with insulin resistance. The factors regulating adiponectin expression and secretion are poorly understood. No study has previously examined the acute post-prandial regulation of adiponectin secretion in detail.

Aims. To compare the acute post-prandial response of plasma adiponectin in lean and obese subjects to determine whether feeding alters plasma adiponectin concentrations that could influence post-prandial glucose and lipid metabolism.

Methods . We studied 13 lean (BMI [mean plus/minus SEM]: 22.5 plus/minus 0.7 kilograms per metre²) and 11 obese (BMI: 41.6plus/minus 3.6 kilograms per metre²) subjects. Plasma adiponectin was measured after an overnight fast and at 15, 30, 60, 120 and 180 minutes following a mixed meal. Plasma adiponectin was measured using a commercially available radioimmunassay.

Results. Fasting adiponectin concentrations were lower in the obese group (mean[95% CI]: 2.9 [2.1-4.1] micrograms per vs litre 8.6 [6.5-11.3] micrograms per litre) and were negatively correlated with HOMA-IR (r=-0.59, p=0.0026), BMI (r=-0.52, p=0.01), waist circumference (r=-0.60, p=0.0018) and age (r=-0.47, p=0.021). After the meal adiponectin concentrations rose four-fold in the obese group, reaching a peak at 60 minutes (baseline: 2.9 [2.1-4.1] vs 60 minutes: 12.1 [8.5-17.4], p<0.0001) and remaining elevated for the remainder of the study. There were no post-prandial changes in plasma adiponectin concentrations in lean subjects. The rise in adiponectin concentrations was partly predicted by age (r=0.57, p=0.0035), HOMA-IR (r=0.48, p=0.018) and AUC glucose (r=0.43, p=0.034).

Conclusions. Plasma adiponectin concentrations rise acutely following a mixed meal in otherwise healthy obese subjects. Given the properties of adiponectin this rise might have important beneficial effects on post-prandial glucose and lipid metabolism.