Expression levels and activity of rat liver lactate dehydrogenase isoenzymes in alloxan diabetes

Abstract

A significant decrease in the activity of lactate dehydrogenase (LDH, EC 1.1.1.27) in liver cells of rats with alloxan diabetes was found due to a decrease in the expression of the corresponding genes. The decrease in the activity of the enzyme under study in experimental type I diabetes was associated with inactivation of the cytoplasmic isoform of LDH. It was found that the level of ldha and ldhb gene transcripts in the liver of healthy rats was higher than in animals with alloxan diabetes. The ldha gene expression demonstrated almost 9-fold decrease, while a decrease in the ldhb gene expression was less pronounced (just 1.25-fold). Probably, the decrease in the rate of functioning of the enzyme under study is associated with a decrease in the intensity of glucose uptake by cells, which leads to inhibition of glycolysis and intensification of all stages of gluconeogenesis, particularly, reversed glycolysis reactions. Thus, the data obtained by us indicate an important role of LDH in the adaptive response of cellular metabolism in the development of type I diabetes mellitus.V pecheni krys s alloksanovym diabetom obnaruzheno znachitel'noe snizhenie aktivnosti laktatdegidrogenazy (LDG, KF 1.1.1.27), obuslovlennoe umen'sheniem ékspressii sootvetstvuiushchikh genov. Éto snizhenie aktivnosti LDG, po-vidimomu, sviazano s umen'sheniem urovnia tsitoplazmaticheskoĭ izoformy LDG. Vyiavleno, chto kontsentratsiia transkriptov genov ldha i ldhb v pecheni zdorovykh krys vyshe, chem u zhivotnykh s alloksanovym diabetom. Prichem ékspressiia gena ldha byla snizhena pochti v 9 raz, togda kak ékspressiia gena ldhb snizhalas' vsego lish' v 1,25 raza. Poluchennye nami dannye svidetel'stvuiut o vazhnoĭ roli LDG v adaptivnoĭ reaktsii kletochnogo metabolizma pri razvitii sakharnogo diabeta I tipa.