Hepatic monooxygenase activity was studied in rats with various resistance to hypoxia during adaptation to cold. Cold-induced change in the concentrations of cytochromes P-450 and bs and the activity of microsomal metabolism of amidopyrine and aniline were shown to be associated with individual resistance to hypoxia. The content of microsomal cytochromes in highly resistant rats did not change on the fifth day of cold exposure. However, the intensity of metabolic reactions decreased. In low-resistance rats, a cold-induced decrease in the concentration of the cytochromes was not accompanied by significant changes in metabolic rates of amidopyrine and aniline.Key Words: individual resistance to hypoxia; hepatic monooxygenases; cold; adaptation Changes in the functional activities of oxidases in mixed of the liver tractions depend on individual resistance to hypoxia [4]. Cytochrome P-450 is represented by several isoforms with various substrate specificity and immunochemical, catalytic, and spectral characteristics [2].The set of cytochrome P-450 isoforms depends on the species, sex, and age of the animal and particularities of effects of xenobiotics entering the body [3,6]. The intensity and the rate of the synthesis if several cytochrome P-450 isoforms increase during adaptation to cold. The role of cytochrome P450 and its isoenzyme composition in animals with various resistance to hypoxia during adaptation to cold received little attention.Here, we studied the activities of hepatic monooxygenases in rats with various resistance to hypobaric oxygenation under cold exposure. MATERIALS AND METHODSExperiments were performed on male Wistar rats weighing 160-180 g. According to their resistance to hypoxia, the rats were divided into highly resistant (HR)Laboratory of Clinical Problems o[ Ecology, Institute of Regional Patholoqy and Pathomorphology, Siberian Division or the Russian Academy of Medical Sciences, Novosibirsk; Department oI Pharmacology, Novosibirsk Medical Institute and low resistant (LR) groups. One week later, the rats were placed into cold room (0-2~ tor 5 days. Material for investigation was collected on fifth days of the cold procedure and on the third day of the post-cold recovery period. The animals kept at 21~ served as control, the content of microsomal cytochromes was measured [7]. Hydroxylase and demethylase activities of the endoplasmic reticulum enzymes were determined with aniline and amidopyrine substrates [5]. Data were analyzed statistically. RESULTSThe concentrations of cytochromes P-450 and b~ in LR rats were 1.6 and 1.4 times higher, respectively, than those in HR rats. Cold exposure led to various changes in the contents of cytochromes P-450 and b s in hepatic microsomal tractions animals with various resistance to hypoxia. In LR rats, the content of tyrochrome P-450 decreased by 14% (compared with COlatrol) the fifth day of adaptation to cold and did not differ from control on the third day of the post-cold period. The content of cytochrome P-450 in HR rats did not differ significantl...
It is shown that the parameters of antipyrine pharmacokinetics during cold exposure depend on individual resistance to hypoxia. High-resistant rats are characterized by less intense metabolism and more rapid normalization of pharmacokinetic parameters than lowresistant rats characterized by shortened elimination half-time corresponding to a more rapid metabolism of xenobiotics under conditions of cold stress.
We studied antipyrine metabolism in rats with different resistance to hypoxia during adaptation to cold stress. Changes in the concentrations of some antipyrine metabolites at low temperature were associated with individual resistance to hypoxia. In low-resistant rats, antipyrine metabolism was suppressed from day 5 of cold exposure to day 3 of the recovery period. In highly resistant rats, antipyrine metabolism was inhibited on day 3 of cold exposure, but returned to normal on day 3 of the recovery period.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.