Background: Aging is associated with a decrease in appetite, energy intake and glucose tolerance. Experimental studies have suggested that ghrelin and obestatin play a role in glucose homeostasis and in the regulation of energy metabolism. However, few studies have been performed on the role of ghrelin and obestatin in middle-aged and old adults.
Methods: In the present study, we investigated the plasma concentrations of ghrelin and obestatin in middle-aged (41-64 years) and old (65-76 years) subjects with newly diagnosed type 2 diabetes mellitus (NDD) and normal glucose tolerance (NGT). We also characterized the relationship among plasma ghrelin and obestatin levels and glucose/lipid metabolism. The fasting plasma ghrelin and obestatin concentrations were analyzed using enzyme immunoassay method.
Results: Plasma obestatin concentrations in diabetic subjects were significantly lower than those in NGT subjects. Plasma ghrelin were negatively associated with fasting glucose, hemoglobin A1c, urine albumin-to-creatinine ratio (UACR) and positively correlated with high-density lipoprotein cholesterol. In addition, plasma obestatin level was correlated negatively with systolic blood pressure, triglycerides and total cholesterol. Furthermore, multiple regression analysis indicated that UACR was a significantly independent predictor of fasting plasma ghrelin levels.
Conclusions: Collectively, ghrelin and obestatin levels may be markers reflecting glucose and lipid conditions in NDD. The lower ghrelin levels may be a potential indicator for renal dysfunction in patients with type 2 diabetes mellitus.