Circulating obestatin levels in normal subjects and in patients with impaired glucose regulation and type 2 diabetes mellitus

Abstract

Obestatin is a novel hormone that is encoded by the Ghrelin gene and produced in the gut. Ghrelin is profoundly orexogenic and adipogenic, increasing food intake and body weight. This new ghrelin-associated peptide behaves as a physiological opponent of ghrelin in rodent animals, but its pathophysiological role in humans remains unknown In this study we investigate whether plasma obestatin level is different in patients with impaired glucose regulation (IGR) and type 2 diabetes mellitus (T2DM). Forty-seven patients with T2DMu, 30 subjects with IGR, and 38 sex- and age-matched normal controls participated in the study. Plasma obestatin levels were measured with a radioimmunoassay. The relationship between plasma obestatin levels and anthropometric and metabolic parameters was also analysed. Plasma obestatin levels were lower in patients with T2DM and IGR than in controls (37.5 +/- 9.2 ng/l and 39.2 +/- 9.7 ng/l vs. 43.8 +/- 8.0 ng/l, P = 0.002 and P = 0.039, respectively). Decreasing concentrations of obestatin were independently and significantly associated with IGR and T2DM. Multiple logistic regression analysis revealed obestatin to be independently associated with IGR and T2DM. In a multiple linear regression analysis, only waist-to-hip ratio and homeostasis model assessment of insulin resistance (HOMA-IR) were independently associated with plasma obestatin level. Our results suggest that obestatin may play a role in appetite regulation in patients with IGR and T2DM.