Effects of metformin and pioglitazone on plasma ghrelin in patients with newly diagnosed abnormal glucose metabolism and abdominal obesity

Abstract

Objective To investigate the effects of metformin and pioglitazone on plasma ghrelin in patients with newly diagnosed abnormal glucose metabolism and abdominal obesity. Methods From April to September 2010, 39 patients with abnormal glucose metabolism (including impaired glucose tolerance and newly diagnosed type diabetes mellitus, glycated hemoglobin A1c(HbA1c)<7%) and obesity were enrolled in the study. They were randomly assigned to metformin group(500 mg tid, n=20, 15 females and 5 males, aged (51±9) years, MET group) or pioglitazone group (30 mg/d, n=19, 11 females and 8 males, aged (53±7) years, PIO group) on the basis of diet and exercise therapy for 3 months.Three males in PIO group with drawed because of itching and edema. At baseline and after 3 months, plasma glucose, serum insulin and ghrelin levels during oral glucose tolerance test(OGTT, 0 min, 0.5, 1.0, 2.0, 3.0 h), body weight, body mass index(BMI), HbA1c, etc were measured.The t test or Wilcoxon rank-sum test was used for statistical analysis. Partial correlation and multiple regression analysis were performed to examine the association between serum ghrelin levels and influencing factors. Results (1)In PIO group, serum ghrelin levels after treatment were OGTT 0 min (1069±467)ng/L, 0.5 h (898±407)ng/L, 1.0 h (812±371)ng/L, 2.0 h (705±328)ng/L and 3.0 h (1059±606)ng/L, respectively. All increased than those before treatment ((905±449), (688±378), (614±358), (572±334)and(720±403)ng/L, Z value was from -2.354 to -3.351, respectively, all P<0.05). (2) In MET group, serum ghrelin levels at OGTT 0 min, 1.0, 2.0, 3.0 h after treatment were (731±241) , (642±208), (525±195), (462±146) and (611± 267)ng/L, respectively. Compared with the ghrelin levels before treatment((731±241) , (642±208), (525±195) , (462±146) and (611±267)ng/L), only the difference at 0 min, 2.0, 3.0 h was statistically significant(all P<0.05). Serum ghrelin levels of MET group at OGTT 0.5, 1.0 and 3.0 h were lower than that of PIO group (Z value was-2.012, -2.006, -2.226, respectively, all P<0.05). Conclusions Compared with those in PIO group, patients treated with metformin lose more weight, but their serum ghrelin levels only partially increase at different point OGTT. This may be one of the reasons why metformin controls weight better. Key words: Diabetes mellitus, type 2; Glucose intolerance; Metformin; Pioglitazone; Ghrelin