Total and acylated ghrelin levels in type 2 diabetic patients: similar levels observed after treatment with metformin, pioglitazone or diet therapy.

Ghrelin, a potent gut-brain orexigenic peptide, has a role in stimulation of food intake and long-term regulation of body weight. Metformin and pioglitazone treatment have different effects on body weight. This discrepancy might be related with the effect of these two drugs on plasma ghrelin levels. We investigated the effect of these two drugs on post-prandial acylated and total ghrelin levels in patients with type 2 diabetes. Eleven patients treated with diet, 12 patients treated with 850 mg/day metformin monotherapy and 12 patients treated with 30 mg/day pioglitazone monotherapy for at least 6 months were enrolled in the study. Plasma acylated and total ghrelin levels were investigated at baseline and at the 60 (th), 120 (th), 180 (th), 240 (th) minutes after a mixed meal test. There were no differences between groups in any of baseline metabolic and anthropometric parameters, including acylated and total ghrelin levels. Acylated and total ghrelin concentrations were suppressed similarly after food consumption, and we could not determine any significant difference between the groups at any time interval. A prolonged postprandial suppression of acylated ghrelin concentrations was observed in the pioglitazone treatment group compared with baseline values. In conclusion, total and acylated ghrelin levels after a mixed meal test were similar in type 2 diabetic patients treated with metformin, pioglitazone or diet therapy alone. These results suggest that changes in body weight during metformin and pioglitazone treatment are not associated with plasma ghrelin levels.