Immunohistochemical localization of cytochrome P-450

Institute of Pediatrics, Eastern Siberian Branch, Academy of Medical Sciences of the USSR, Irkutsk. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 112, No. 12, pp. 646–647, December, 1991.     

Induction of cytochrome P-450 and an immune response by phenobarbital,free and covalently bound with albumin

Definite interaction exists between the induction of microsomal enzymes and induction of the immune response to foreign substances. The loss by phenobarbital of its ability to induce the cytochrome P-450-hydroxylase system when bound covalently with albumin, coupled with the acquisition by phenobarbital of ability to induce a lymphocytic immune system reflects the ability of the two defensive systems of the body — hydroxylase and immune — to interact with foreign compounds of low and high molecular weight. The cytochrome P-450-hydroxylase system of the liver and other tissues is designed to protect the body against the action of low-molecular-weight hydrophobic compounds. The immune system is responsible for the protective effect against high-molecular-weight foreign substances.Laboratory of Enzymology and Bioenergetics, Central Research Laboratory, N. I. Pirogov 2nd Moscow Medical Institute. Department of Immunopharmacology, Research Institute for Biological Testing of Chemical Compounds, Kupavna. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 3, pp. 323–324, March, 1980.     

Resistance of different forms of cytochrome P-450 of rat liver to factors destabilizing the microsomal membrane

The effect of factors destabilizing the membrane of the liver microsomes on the spectral properties of cytochrome P-450 (P-448) was investigated in intact rats and rats receiving phenobarbital (PB) or 3-methylcholanthrene (MC). Considerable resistance of microsomes induced by PB and MC to enzymic and nonenzymic peroxidation of polyunsaturated fatty acids of membrane phospholipids was discovered. A clear difference was shown in the sensitivity of cytochrome P-448 and cytochrome P-450 of intact rats and rats receiving PB to in vitro treatment with sodium deoxycholate. The results indicate structural changes in the microsomal membrane during induction by PB and MC, which are two different types of inducers of the monooxygenases of the liver.Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 553–555, May, 1977.     

Effect of emotional-painful stress on cytochrome P-450 induction in the rat liver

Laboratory of Bioenergetics, Research Institute of Pharmacology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, A. V. Val'dman.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 108, No. 7, pp. 48–50, July, 1989.     

Changes of the level of cytochrome P-450 and NADPH-cytochrome P-450 reductase in rats with hereditary degeneration of the retina

In animals with hereditary degeneration of the retina the level of cytochrome P-450 in the brain microsomal fraction is found to be higher than that in healthy animals. In rats with hereditary degeneration of the retina the activity of NADPH-cytochrome P-450 reductase is unchanged in all tissues examined except for the retina, where it is markedly higher than in healthy animals on postnatal day 90. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 3, pp. 259–261, March, 1994     

Cytochrome P-450 content and its induction in primary rat liver tumors

Laboratory for the Study of Carcinogens and Laboratory of the Mechanisms of Carcinogenesis, All-Union Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Trapeznikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 105, No. 2, pp. 198–200, February, 1988.     

Liver microsomal cytochrome: P-450p and P-450h activity and blood corticosteroid levels of experimental animals exposed to physical factors

Laboratory of Experimental Therapy, Institute of Balneology, Ministry of Health of the Ukraine, Odessa. Department of Cell Physiology and Pathology, Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of Medical Sciences, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences V. Ya. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 5, pp. 498–500, May, 1992.     

Heterogeneity of cytochrome P-450 distribution in the hepatic lobule revealed by carbon tetrachloride

The concentration of cytochrome P-450 was compared with the histological picture of development and elimination of necrotic foci in the liver of CBA mice after inhalation of CCl₄ vapor. After 2 h the cytochrome P-450 content was reduced by 49%, and after 17, 24, and 48 h by 84%; only about 40% of the area of the hepatic lobule underwent necrosis under these circumstances. It is suggested that the selectivity of injury by CCl₄ to the central lobular hepatocytes is connected with the sharp difference in cytochrome P-450 content in different zones of the lobule.Laboratory of Cytology, N. K. Kol'tsov Institute of Developmental Biology, Academy of Sciences of the USSR. Laboratory of Physical Chemistry of Biomembranes, M. V. Lomonosov Moscow State University. (Presented by Academician of the Academy of Medical Sciences of the USSR S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 4, pp. 364–366, April, 1979.     

Two-step activation of valproic acid (VPA) by hepatic cytochrome P-450

There is now considerable evidence that the unsaturated metabolite of VPA, delta 4-VPA, may be responsible for VPA-induced hepatic injury. It is proposed that VPA is activated to a hepatotoxic species by a two-step cytochrome P-450-mediated mechanism consisting of 1) desaturation and 2) unknown activation, possibly by epoxide formation, involving one or more P-450 isozymes with subsequent covalent binding to cellular macromolecules. In vivo and in vitro experimental protocols are indicated for testing the proposed hypothesis.