Brief report Dimethylarginines in patients with type 2 diabetes mellitus: Relation with the glycaemic control Ayten Can a , Seldag Bekpinar a, *, Figen Gurdol a , Yıldız Tutuncu b , Yesim Unlucerci a , Nevin Dinccag b a Department of Biochemistry, Istanbul Faculty of Medicine, Istanbul University, Capa 34093, Istanbul, Turkey b Department of Endocrinology, Istanbul Faculty of Medicine, Istanbul University, Capa 34093, Istanbul, Turkey 1. Introduction Symmetric and asymmetric dimethylarginines (SDMA and ADMA), naturally occurring arginine analogues, are produced during post-translational methylation of arginine residues by protein arginine methyl transferases (PRMTs) in nuclear proteins and subsequently released by proteolysis [1]. Owing to its inhibitory effect on NO synthase, ADMA is important in cardiovascular diseases whereas its equivalently produced counterpart, symmetric dimethylarginine, has no such a role [2]. The metabolic fate of these isomers is different, too. SDMA is fully eliminated via kidney and correlated well with the parameters of renal function [3], while ADMA is mostly degraded in liver by the enzyme dimethylarginine dimethy- laminohydrolase (DDAH), which is sensitive to oxidative stress [4,5]. Impairment of DDAH activity selectively increases circulating ADMA, whereas SDMA remains un- changed. The ADMA/SDMA ratio is accepted as a rough estimate of the DDAH activity, a low ratio being suggestive of high activity. A positive relationship between long-term glycaemic control and plasma ADMA levels existed in patients with diabetes mellitus (DM) and associated with micro- and macrovascular complications [6–8]. On the other hand, a negative relationship has been reported between SDMA and insulin resistance [9,10]. Bo¨ ger et al. have observed identical ADMA levels in diabetic and non-diabetics subjects, which were positively associated with mortality in the latter [11]. All these results suggest a complex and variable effect of chronic hyperglycaemia on plasma levels of dimethylargi- nines. Therefore, we aimed to examine the relation between plasma dimethylarginines and glycaemic control in type 2 diabetes. d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 9 4 ( 2 0 1 1 ) e 6 1 – e 6 4 a r t i c l e i n f o Article history: Received 25 July 2011 Accepted 8 August 2011 Published on line 1 September 2011 Keywords: Symmetric dimethylarginine Asymmetric dimethylarginine HbA1c Type 2 diabetes a b s t r a c t We tested the relationship between plasma levels of dimethylarginines (ADMA and SDMA) and glycaemic control in 43 type 2 diabetic patients. Type 2 diabetics with poor glycaemic control (HbA1c > 6.5) had significantly lower SDMA and higher ADMA concentrations than those with well-controlled glycaemia (HbA1c < 6.5). # 2011 Elsevier Ireland Ltd. All rights reserved. * Corresponding author. Tel.: +90 212 4142000x32352; fax: +90 212 6215642. E-mail address: seldabekpinar@hotmail.com (S. Bekpinar). C o n t e n t s l i s t s a v a i l a b l e a t S c i e n c e D i r e c t Diabetes Research and Clinical Practice journal homepage: www.elsevier.com/locate/diabres 0168-8227/$ – see front matter # 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.diabres.2011.08.008