Plasma ghrelin and peptide YY levels in patients with type 2 diabetes before and after metformin treatment

Abstract

Objective To investigate the effects of metformin on plasma ghrelin and peptide YY (PYY)levels in newly-diagnosed type 2 diabetic patients,and to study the impact of metformin on body weight.Methods A prospective nested case-control study was designed as a research protocol.Sixty four newly-diagnosed type 2 diabetic patients were treated with metformin for 12 weeks.The patients were divided into two groups:weight loss group and non-weight loss group according to the changes in body weight after metformin treatment.Fasting plasma ghrelin and PYY levels and other metabolic parameters were measured before and after metformin treatment.Results Fasting plasma ghrelin level was significantly decreased in the patients after metformin treatment [ ( 10.71 ±2.68 vs 11.81 ±3.19 )ng/ml,P＜0.05 ].Fasting plasma PYY level was significantly increased in patients after metformin treatment [ ( 136.86+39.14 vs 128.42+37.31 ) pg/ml,P＜0.05 ].After metformin treatment,43.7％ of the patients lost body weight significantly.Fasting plasma ghrelin level was decreased by 16.6％ after treatment in the weight loss group,as compared with 6.2％ in non weight loss group( P＜0.05 ).Fasting plasma PYY level was increased by 10.8％ after treatment in the weight loss group,as compared with 3.5％ in the non-weight loss group (P ＜ 0.05 ).Conclusions The fasting plasma ghrelin level in the weight loss group was lowered more significantly compared with that in the non-weight loss group after metformin treatment.The fasting plasma PYY level in the weight loss group was elevated more significantly as compared with that in the non-weight loss group after metformin treatment.The mechanism remains to be further studied. Key words: Metformin; Diabetes mellitus, type 2; Body mass index; Ghrelin; Peptide YY