Gen. Physiol. Biophys. (2002), 21, 337—344 337 Short Communication Effects of Aminoguanidine Schiff’s Base on Biomarkers of the Oxidative Stress, 4-hydroxy-2-nonenal and Conjugated Dienes, in the Model Diabetes Mellitus P. Korytár 1 , M. Molnárová 1 , M. Sivoňová 1 , I. Žitňanová 1 , O. Uličná 2 , A. Liptáková 1 , J. Čársky 1 and Z. Ďuračková 1 1 Department of Medical Chemistry, Biochemistry and Clinical Biochemistry, Medical Faculty, Comenius University, Bratislava, Slovakia 2 Pharmacochemical laboratory, III. Internal clinic, Medical Faculty, Comenius University, Hlboká 7, 811 05 Bratislava, Slovakia Abstract. Diabetes mellitus evoked by streptozotocine in rats is associated with the oxidative stress. We examined the effect of Schiff’s base 2,5-dihydroxybenzal- dehyde with a well-known antidiabetic drug aminoguanidine, 2,5-dihydroxybenzi- lideneaminoguanidine (BAG) on the production of markers of oxidative stress such as 4-hydroxy-2-nonenal (4HNE) and conjugated dienes in diabetic rats. BAG ad- ministration did not affect glucose level in diabetic rats but significantly decreased the production of 4HNE and conjugated dienes. On the other hand, BAG caused the elevation of conjugated dienes and an insignificant increase of 4HNE levels in the control animals. Key words: Diabetes mellitus — Oxidative stress — Antioxidant — 4-hydroxy- 2-nonenal — 2,5-dihydroxybenzilideneaminoguanidine Introduction The imbalance between the production and removal of the oxygen and nitrogen reactive species followed by the damage of biomacromolecules is called oxidative stress. The oxidative stress plays an important role in the etiopathogenesis of many diseases and participates in the development of their chronic complications. For example significantly increased formation of products of the oxidative damage to lipids, proteins and DNA was detected in the blood and tissues of Diabetes mel- litus (DM) patients. On the other hand these patients contain decreased levels of antioxidants (Muchová 1999; Čársky 1999; Zeman et al. 2000). Oxidation of lipoproteins is a characteristic event in the oxidative stress caused by the oxidative damage to polyunsaturated fatty acids. Especially lipids and other Correspondence to: Prof. Zdeňka Ďuračková, PhD., Department of Medical Chem- istry, Biochemistry and Clinical Biochemistry, Medical Faculty, Comenius University, Sasinková 2, 811 08 Bratislava 1, Slovakia. E-mail: durackova@fmed.uniba.sk