Search

Inborn mitochondrial diseases (MD) may result from molecular defects involving the mitochondrial or the nuclear genome, so they may be transmitted maternally or as Mendelian traits; some cases occur sporadically. Numerous secondary causes of mitochondrial disorders are also known. Impairment of mitochondrial oxidation leads to the defective energy production, and further, to cellular damage. MD should be suspected when progressive signs occur, especially involving nervous system and muscles; other organs as heart, liver and kidney may also be affected.

Male Wistar rats were exposed to NH4F in concentration corresponding to mean annual limit of fluoride compounds in the atmospheric air. After 3, 6 and 9 months a microsomal fraction was isolated from the liver, and the composition as well as the metabolic activity of this fraction was determined. The content of microsomal protein increased after 3-month-long period of experiment, and subsequently it dropped after the period of 9 months. The content of phospholipids decreased after 3 months. The content of microsomal cholesterol was particularly high after a 6-month-long experiment. There were also changes in the contents of individual phospholipid fractions, and fatty acids of phospholipids. The content of cytochrome P-450, cytochrome b5 and activity of NADH-cytochrome b5 reductase did not change. Activity of NADPH-dependent reductase of cytochrome c--decreased after the period of 9 months. Moreover, as consequence of changes in the activity of cytochrome P-450 system and the endoplasmic reticulum composition, alterations were observed in the metabolism of the tested substrates i.e. aniline and aminopyrine. The aniline turnover was inhibited after 6 and that of aminopyrine after 9 months experiment. The observed changes may prove that the detoxication capacity of the liver was impaired due to being exposed to ammonium fluoride.

The aim of the work was an attempt to estimate the changes taking place in the hepatic microsomes of a rat, in the early phase of newborn life, maturation and growing old after peritoneal benzene administration. The observations were led on a smooth and rough endoplasmic reticulum fractions. The object of experiment were P-450-dependent monooxygenases cytochrome. In the experiment the female Wistar rats at age: 5-, 10-, 15-, 30-, 60 days old and 18 months old were used. 6 hours before decapitation the rats were given benzene in peritoneal way, in dose 250 mg per kg of the body weight. In a smooth and rough microsomes were indicated: protein contents, cytochromes P-450 and b5 contents and also the activity of NADPH-cytochrome c and NADH-cytochrome b5 reductases, aniline hydroxylase and 4-aminopyrine demethylase. Benzene revealed a changing influence on protein contents. In the rough fraction the negative influence was observed, but in the smooth fraction a clear stimulation was observed in certain age intervals. The influence of the discussed hydrocarbon on the cytochrome P-450 contents was similar in both subfractions. In animals entering puberty benzene was found to reduce P-450 contents. The activity of NADPH-cytochrome c reductase, 4-aminopyrine demethylase, and aniline hydroxylase was modified to different degrees depending on age of the animals, the inhibitory effect being prevailing. The contents of cytochrome b5 in SER and RER didn't change in extreme age groups but it was remarkably reduced during puberty. A significantly changing influence of benzene on the activity of NADH-cytochrome b5 reductase was observed both in smooth and rough fractions.