The NADH-ubiquinone reductase and succinate dehydrogenase activity in the rat kidney mitochondria under the conditions of different protein and sucrose content in the diet

Abstract

NaDh-ubiquinone reductase (Ec 7.1.1.2) and succinate dehydrogenase (Ec 1.3.5.1) activity, the levels of total ubiquinone and its redox forms, and the degree of oxidative modification of mitochondrial proteins in the rat kidney were investigated. It was found that when consuming a low-protein diet there is a decrease in NaDh-ubiquinone reductase and succinate dehydrogenase activity by 1.4-1.7 times, a 20% decrease in total ubiquinone and a quantitative redistribution of its oxidized and reduced form with a predominance of oxidized form. Under the studied conditions, there is no accumulation of carbonyl derivatives, but the level of free Sh-groups is significantly reduced compared with control. at the same time, in animals consuming a high-sucrose diet there is an increase in NaDh-ubiquinone reductase and succinate dehydrogenase activity by 1.5-2 times and maintenance of the total ubiquinone at the control level against the background of redistribution of its redox forms, namely a decrease in reduced ubiquinone and an increase in oxidized ubiquinone on average by 1.5 times. In addition, there is an intensification of the reactions of free radical damage of mitochondrial proteins in kidney cells, as evidenced by an increase in the level of carbonyl derivatives and a significant decrease in the level of free protein Sh-groups by approximately 1.4-1.5 times. the most pronounced changes in the studied indicators are found in animals that consumed a low-protein/ high-sucrose diet. In particular, an excessive consumption of sucrose on the background of protein deficiency is accompanied by a reduction of NaDh-ubiquinone reductase and succinate dehydrogenase activity by 1.7-2 times, a decrease in total ubiquinone level by approximately 1.4 times, and a two-fold decrease in reduced ubiquinone against the background of intensification of the free radical oxidation of mitochondrial proteins, which can be considered as a prerequisite for the impairment of the renal function under the conditions of carbohydrate-protein imbalance. K e y w o r d s: nutrients, kidney, NaDh-Ubiquinone reductase, succinate dehydrogenase, ubiquinone, carbonyl derivatives, protein Sh-group.

Activity of respiratory chain cytochrome complexes and cytochromes content in the rat kidney mitochondria under different nutrients content in a diet

“…Changes in the activity of the cytochrome part of the respiratory chain enzymes in case of excessive sucrose intake can be associated with several reasons. The decrease in the activity of Comple xes III and IV can be caused by oxidative damage to mitochondrial proteins and occurrence of hyperglycemia, as was found in our earlier studies [26,27].…”

“…Moreover, hyperglycemia is associated with an increase in the levels of Rieske and core 2 proteins -structural components of Complex III, which is considered a compensatory mechanism for restoring the activity of ubiquinol cytochrome c oxidoreductase. Besides, taking into account that reduced ubiquinone is the coenzyme of ubiquinolcytochrome c oxidoreductase, and its levels in the kidneys are decreased under the conditions of nutrient imbalance [26], this can be considered as another cause of the reduced activity of the respiratory chain complexes. Since the important structural components of Complexes III and IV are hemecontaining proteins -cytochromes, one of the reasons for the drop in the ubiquinolcytochrome c oxidase and cytochrome oxidase activity under the studied conditions could be changes in their levels.…”

Pyruvate Dehydrogenase Complex Activity in the Rat`s Kidneys Under Conditions of Toxic Acetaminophen Damage With Protein Deficiency

“…Регенерація NAD+ з NADH відбувається у мітохондріях у процесі окисного фосфорилювання, що необхідно для забезпечення проходження гліколізу (Jialal end Sokoll, 2015). Проте, як показано у наших попередніх дослідженнях (Voloshchuk et al, 2022), за умов токсичного впливу ацетамінофену функціонування дихального ланцюга порушується, тому, ймовірно, поповнення пулу NAD+ відбувається за допомогою реакції перетворення пірувату в лактат. Відповідно утворений лактат не може знову окислитися до пірувату через дефіцит NAD+ і тому акумулюється (Абдилова и др., 2015).…”

“…Отримані нами результати, імовірно, свідчать про інтенсифікацію анаеробного гліколізу як головного постачальника енергії у клітинах нирок за умов інтоксикації ацетамінофеном. Попередніми дослідженнями показано, що за умов передозування ацетамінофеном спостерігається порушення ензиматичної активності комплексів дихального ланцюга у нирках, що в свою чергу може призводити до порушення окисного фосфорилювання та виснаження пулу ATP (Voloshchuk et al, 2022). У той же час нирки як важливий гомеостатичний орган потребують великої кількості ATP для здійснення життєво важливих функцій, зокрема реаб-сорбції, виділення кінцевих продуктів метаболізму, біосинтетичних процесів, регуляції водно-сольового обміну, тому переключення на анаеробний шлях енергозабезпечення за досліджуваних умов видається цілком логічним.…”