[The cytochrome P-450-dependent mono-oxygenase system of the liver and interleukin-1 production by the macrophages in adjuvant arthritis in rats under the influence of beta-carotene]. / Tsitokhrom P-450-zavisimaia monooksigenaznaia sistema pecheni i produktsiia interleikina-1 makrofagami pri ad''iuvantnom artrite u krys pod vliianiem beta-karotina.

A relationship between the production of interleukin 1 (IL-1) by macrophages from adjuvant-induced arthritic rats and cytochrome P-450-dependent hepatic microsomal monooxygenase was studied. The synthesis of IL-1 by splenic and peritoneal macrophages on day 17 postadjuvant treatment was not altered, but the hepatic cytochrome P-450 levels and monooxygenase activity were significantly decreased. Beta-carotene treatment of arthritic rats reduced hind paw swelling and concurrently stimulated the ability of macrophages to secrete IL-1 and increased the cytochrome P-450 levels and the activity of hepatic monooxygenase. The findings did not establish a definite relationship between the production of IL-1 by systemic macrophages on the one hand, and the hepatic cytochrome P-450 levels a and monooxygenase activity on the other hand. It thus appears that IL1 is unable to play a role of a mediator between the immune system and the hepatic cytochrome P-450-dependent monooxygenase system of rats with adjuvant-induced arthritis.

[The effect of beta-carotene on the development of adjuvant arthritis and interleukin-1 production in rats]. / Vliianie beta-karotina na razvitie ad''iuvantnogo artrita i produktsiiu interleikina-1 u krys.

The production of interleukin 1 (IL1) by peritoneal and splenic macrophages from rats with adjuvant-induced arthritis on day 17 postadjuvant treatment was not altered compared with normal. Treatment of arthritic rats with beta-carotene reduced hind paw swelling and significantly increased ability of macrophages to secrete IL1 as well as stimulated spontaneous proliferation of splenic lymphocytes. No direct relationship between the release of IL1 from peritoneal and splenic macrophages and increase of hind paw swelling was revealed.

[Blood cobalamins and xenobiotic-metabolizing enzymes in rat liver in adjuvant arthritis]. / Kobalaminy krovi i fermenty metabolizma ksenobiotikov v pecheni krys pri ad''iuvantnom artrite.

Changes in the total cobalamin content and spectrum of individual forms of these vitamins in blood cells and plasma as well as the activities of enzymatic systems of xenobiotic metabolism in liver microsomes of rats with experimental adjuvant arthritis (AA) have been studied. The total cobalamin content in the blood plasma of rats with AA was increased in comparison with intact animals; however, leucocytes from AA rats were deficient in methylcobalamin (MeCbl). A correlation was found between the ratios of individual cobalamin forms and their total content which was differently expressed in experimental and control animals. The development of AA was associated with marked inhibition of the cytochrome P-450-dependent monooxygenase system of the liver and glutathione transferase. The possibility of correction of these disturbances by MeCbl is discussed.

[The vitamin D endocrine system and bone tissue mineral metabolism in rats with adjuvant arthritis: the effect of 1,25-dihydroxyvitamin D3]. / Endokrinnaia sistema vitamina D i mineral'nyi obmen kostnoi tkani u krys s ad''iuvantnym artritom: vliianie 1,25-digidroksivitamina D3.

Adjuvant arthritis was induced in male rats by injecting bacillus Calmette-Guèrin in mineral oil in a hindpaw. A decrease in bone density, calcium and phosphorus content due to polyarthritis was found in the tibia of the noninjected hind leg. Arthritic rats demonstrated serum 1,25-dihydroxyvitamin D deficiency along with constant level of 25-hydroxyvitamin D. The disease caused a significant expression of 1,25-dihydroxyvitamin D3 receptors in lymphocytes. Arthritic rats were treated with 1,25-dihydroxyvitamin D3 (0.15 mg/kg/day orally) for 35 days. The treatment prevented the development of osteoporosis and a decrease of 1,25-dihydroxyvitamin D levels as well as reduced the expression of 1,25-dihydroxyvitamin D receptors in lymphocytes.

[Vitamin B 12 metabolism and the status of sulfhydryl groups in protein-choline deficiency in rats. Effects of methyl- and adenosylcobalamins]. / Obmen vitamina B 12 i sostoianie SH-grupp pri belkovo-kholinovoi nedostatochnosti u krys. Vliianie metil i adenozilkobalaminov.

The effect of low protein choline-deficient diet on total vitamin B12 content and individual cobalamin level in the blood serum and liver of rats was determined. Moreover the total and non-protein SH-group content and glutathione transferase activity in the liver of rats were studied. Total cobalamin content increased in the blood serum, but it did not change in the liver of rats fed choline-deficient low protein diet. Total and non-protein SH-group level as well as glutathione transferase activity in the liver decreased significantly. The causes of changes revealed are discussed. Methylcobalamin (but not adenosylcobalamin) administration normalized individual cobalamin level in the blood serum. Administration of both methylcobalamin and adenosyl-cobalamin resulted in total SH-group content restoration whereas non-protein SH-group level and glutathione transferase activity were restored only in methylcobalamin-treated rats.

[The monooxygenase system, lipid peroxidation in the liver and vitamin B12 metabolism in experimental poisoning of rabbits with phenylhydrazine]. / Monoksigenaznaia sistema, perekisnoe okislenie lipidov v pecheni i obmen vitamina B12 pri éksperimental'nom otravlenii krolikov fenilgidrazinom.

It has been demonstrated that phenylhydrazine poisoning results in a significant activation of lipid peroxidation, reduction of dimethylaniline N-demethylation and NADPH-2.6-dichlorophenolindophenol and NADPH-cytochrome c-reductase activities as well as in the stimulation of the NADPH-nitrotetrazolium reductase activity in rabbit liver microsomes. In addition, phenylhydrazine administration causes disturbances in vitamin B12 metabolism which are manifested as changes in total cobalamin pool and in the spectrum of vitamin B12 individual physiologically active forms in the blood.

[Comparative study of the effect of vitamin B12 coenzymes on monooxygenase system and lipid peroxidation in the liver of rabbits poisoned with phenylhydrazine]. / Sravnitel'noe izuchenie vliianiia kofermentnykh form vitamina B12 na monooksigenaznuiu sistemu i perekisnoe okislenie lipidov v pecheni krolikov pri otravlenii fenilgidrazinom.

Distinct activation of lipid peroxidation, reduction in N-demethylation of dimethyl aniline and in NADPH-dependent electron transport chain were observed in liver microsomes of rabbits poisoned with phenyl hydrazine. Methylcobalamine and adenosyl-cobalamine, two coenzyme forms of vitamin B12, were firstly shown to serve as modulators of the monooxygenase system, whereas methyl-cobalamine proved to be inductor and adenosylcobalamine-repressor of the system. Administration of methylcobalamine into the poisoned rabbits stimulated much higher the activities of dimethyl aniline N-demethylase, aniline p-hydroxylase, NADPH-cytochrome P-450- and NODH-cytochrome b5 reductases as compared with normal state, while adenosylcobalamine inhibited the reduction of all the monooxygenase system patterns studied. At the same time, both these coenzymes contributed to normalization of lipid peroxidation in liver microsomes of poisoned rabbits.

[Effect of methylcobalamin and adenosylcobalamin on the process of hematopoiesis and vitamin B12 exchange in experimental phenylhydrazine-induced anemia in rabbits]. / Vliianie metilkobalamina i adenozilkobalamina na protsessy krovetvoreniia i obmen vitamina B12 pri éksperimental'noi fenilgidrazinovoi anemii u krolikov.

Poisoning of rabbits with phenylhydrazine resulted in development of haemolytic hyperchromic anemia accompanied by impairment of hemopoiesis in bone marrow as well as by an increase of total vitamin B12 content in blood. The ration of individual forms of cobalamins was firstly estimated in blood serum of healthy rabbits and of the animals treated with phenylhydrazine. Distinct decrease in the methyl cobalamin content was observed in blood serum during spontaneous recovery. Administration of methyl cobalamin led to complete normalization of some blood and hematopoiesis patterns, as well as to restoration of total cobalamins content and the spectrum of their individual forms. Adenosyl cobalamin exhibited distinctly lower effect on the patterns studied. The data obtained suggest that methyl cobalamin possessed a lot of advantages in treatment of hemolytic anemias.

[Cobalamins in normal and pathological states (review)]. / Kobalaminy v norme i pri patologii (obzor).

Four cobalamines (methyl-, hydroxy-, adenosyl- and cyancobalamines) are considered as natural forms of vitamin B12 in human and animal tissues. Methyl- and adenosylcobalamines are the coenzymes of more than 10 enzymes, catalyzing important reactions of lipid, carbohydrate and protein metabolism. The four natural forms of vitamin B12 are interconverted in presence of corresponding enzymatic systems. Content of individual forms of cobalamines and of corresponding coenzymes depends on the function of enzymatic systems involved in their synthesis as well as on the enzymes, which use these derivatives as coenzymes. Spectra of cobalamines in human and animal bodies are dynamic systems, distinctly and specifically responding to various effects. The data on the ratio of individual forms of vitamin B12 in human and animal blood and tissues as well as their alterations under physiological and pathological conditions are discussed. Differentiation of individual physiologically active forms of vitamin B12 and their estimation is very important and may contribute to elucidation of molecular mechanisms of impairments in cobalamine metabolism in various diseases.

[Substrate specificity of adenosylcobalamin-dependent glycerol dehydratase. Interaction with enantiomers of 1,2-propanediol]. / Substratnaia spetsifichnost' adenozilkobalaminzavisimoi glitseroldegidratazy. Vzaimodeistvie s énantiomerami 1,2-propandiola.

Adenosylcobalamin-dependent glycerol dehydratase was shown to catalyze the conversion of both enantiomers of 1.2-propanediol. The kinetic constants for the dehydration reaction of (R)- and (S)-1.2-propanediol appear to be different. The enzyme preferentially binds 1.2-propanediol in the (S)-configuration; however, the rate of (S)-1,2-propanediol dehydration is 2 times less than that of (R)-1.2-propanediol. The catalytic conversion of 1.2-propanediol enantiomers is accompanied by the enzyme inactivation. During dehydration of (R)-1.2-propanediol the enzyme is inactivated at a higher rate than during the (S)-enantiomer dehydration. The turnover number of the enzyme calculated as a ratio of the rate constants of catalysis and inactivation does not practically depend on the substrate configuration. Consequently, the changes in the configuration of the substrate, 1.2-propanediol, similarly affect the rate-limiting steps of the catalytic and inactivation processes. It is assumed that the (R)- and (S)-enantiomers of 1.2-propanediol are bound at the substrate site of glycerol dehydratase by three identical points.

[Interaction of substrates and their analogs with adenosylcobalamine-dependent glycerol dehydratase]. / Vzaimodeistvie substratov i ikh analogov s adenozilkobalaminzavisimoi glitseroldegidratazoi.

The interaction of AdoCbl-dependent glycerol dehydratase with the substrates (glycerol, 1,2-propandiol, ethylene glycol) and their analogs (aliphatic diols) was studied kinetically. It was found that all the diols tested are competitive inhibitors of the enzyme with respect to substrates. The arrangement of hydroxyl groups in the molecule, the length of the carbohydrate chain and the nature of the substituent at the C-3 atom are essential for the binding of diol in the active center. The ternary enzyme-AdoCbl-substrate (analog) complexes are subjected to specific inactivation at a rate, which depends on the chemical structure of the substrate (analog). The constants for inactivation and dissociation of the ternary complexes were determined. It was shown that in contrast to the double complexes (enzyme-AdoCbl), the inactivation of the ternary complexes does not depend on oxygen. Some aspects of the mechanism of specific inactivation of glycerol dehydratase are discussed.

[Effect of environmental factors on inactivation of B12-dependent glycerol dehydratase from Aerobacter aerogenes]. / Vliianie faktorov sredy na inaktivatsiiu B12-zavisimoi glitseroldegidratazy iz Aerobacter aerogenes

Effect of temperature, pH and univalent cation on kinetics of self-activation of B12-dependent glycerol dehydratase (GD) from Aerobacter aerogenes with Co alpha-[alpha-(5,6-dimethylbenzimidazolyl]-Co beta-adenosylcobamide (AdoCbl) was investigated. The activation energy of the process of GD inactivation is found to be 3.9 kkal/M, the effect of pH on GD inactivation being insignificant. Monovalent cation is not required for the formation of GD-AdoCbl complex, but it protects the complex from selfinactivation. The rate of GD inactivation greatly depends on concentration of monovalent cations. Effect of K+, Rb+, Cs+, Tl+ and NH4+ cations, which are enzyme cofactors, qualitatively differs from the effect of Na+ and Li+, which are inactive in a catalytic reaction. The presence of at least two cation-binding sites in GD molecule is suggested. Possible mechanism of the effect of environmental factors in self-inactivation of GD-AdoCbl complex is discussed.

[Role of monovalent cations in reactions catalyzed by glycerol dehydrase from Aerobacter aerogenes].

Cobamide-dependent glyceroldehydrase (GDH) is shown to have an absolute requirement in monovalent cations: K+, NH4+, Tl+, Rb+ and Cs+. Dependencies of initial dehydratation rates of three substrates: glycerol, ethyleneglycol and 1,2-propandiol on the concentration of K+ are studied. Km values for K+, NH4+ and Tl+ are calculated to be 7-10-3, 4-10-3 and 1-10-3 M respectively. Effect of K+ on Km values for glycerol and coenzyme and on maximal reaction rate is investigated. It is shown that the apparent affinity of the substrate to the enzyme does not depend on monovalent cation; the apparent affinity of the coenzyme somewhat changes with the change of K+ concentration. Maximal reaction rate increases with the increase of K+ content. On the basis of kinetic data obtained possible mechanism of the activating effect of monovalent cations in reactions, catalyzed by GDH, is discussed.