Aminoguanidine partially prevents the reduction in liver pyruvate kinase activity in diabetic rats

BACKGROUND: Low molecular weight aldehydes and carbonyl compounds which are derived from glucose metabolism are prevalent in diabetic plasma. These compounds react to amino groups of Lys and Arg and lead to the formation of advanced glycation end products (AGEs). This modification changes the function of the proteins. The present study aimed to survey the effect of diabetes on rat liver pyruvate kinase activity and to show the inhibitory effect of aminoguanidine (AG). MATERIALS AND METHODS: Male Wistar rats (n = 18, 6 to 8 weeks old) were divided randomly in three groups: the first group as control; second and third groups were induced diabetes using streptozocin. Third group received AG orally for 8 weeks after diabetes induction. Liver cell homogenate was prepared from all studied groups and L-type pyruvate kinase was separated from the homogenate. Pyruvate kinase activity was determined in both liver cell homogenate and extracted L-type PK. The PK activity was compared in all samples between groups. RESULTS: PK activity in isolated form and in liver cell homogenate was lower in diabetic rats as compared to control group. AG-treated group showed higher PK activity compared to untreated diabetic group; however, the difference was not significant. Non-significant difference in PK activity between AG-treated diabetic and non-diabetic (control) group indicated the inhibitory effect of AG in glycation of PK. CONCLUSION: The obtained results showed PK activity decreased in diabetic rats and AG can partially prevent the reduction in PK activity.