Hydroperoxide of methyl linoleate-^<14>C was prepared from linoleic acid-l^<14>C by esterification and autoxidation. After chromatographic purification, the hydroperoxide was decomposed by heating in the inert gas at 100℃. The rats were divided into four groups and were fed with these preparations via stomach tube. Distribution of radioactivity in various organs in the rats was compared in these groups. The distribution of ^<14>C in the rat tissues fed with hydroperoxide resembled to those given the heat decomposition products, but it was quite different from that in the control. The result shows that hydroperoxide may be absorbed as decomposition products into the rat body. The distribution of ^<14>C in the rats fed with the peroxide and vitamin E was almost the same as that in the control. From this result, it is suggested that vitamin E may act as the peroxide decomposing agent, besides as free radical inhibitor, previously known.

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The absorption and excretion of cyclocarbothiamine (CCT) were investigated when it was administered orally for human and rat. After oral administration of CCT for healthy subjects, the blood level and urinary excretion of thiamine were markedly higher as in case of the other modified thiamine derivatives than those of thiamine hydrochloride. When CCT was given to rat, the thiamine values of blood, liver, kidney and muscle were markedly elevated and it was observed that the phosphorylation of thiamine is also increased.

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Chronic toxicity of riboflavin tetrabutyrate was examined using male albino rats of Wistar strain as test animals. They were administered compulsorily with 2.0 g/day/kg of body weight, 1.0 g/day/kg, or 0.5 g/day/kg of riboflavin tetrabutyrate. The body weight gains of these animals were the same with those of control animals. After 6 months' feeding, the measurement of weight of each organ, hematological examination on blood, and histological investigation on organs and tissues were performed. No difference was found between animals fed with riboflavin tetrabutyrate and controls, indicating that this vitamin derivative has no chronic toxicity.

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Young Wistar rats (male, 15-20 days old ) were injected with 750μc of myoinositol-2^3H per kg body weight, and its incorporation into free myoinositol pools and phospholipid fractions of the liver, kidney and brain was investigated. The rates of incorporation of ^3H in both fractions of these three organs were compared to each other : the highest values were found in the kidney, and the lowest in the brain. The specific activities found in free myoinositol pool and in monophosphoinositide fraction of the liver at 1 hour after the injection were determined to be 1.85×10^5dpm/μmole and 1.45×10^5dpm/μmole, respectively. However, the total amount of the radioactive myoinositol incorporated into the monophosphoinositide was 2.5 times larger than that incorporated into the free myoinositol pool. It is therefore suggested that in the liver, exogeneous myoinositol is not so much diluted by endogeneous myoinositol in phospholipid biosynthesis.

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N-oxide forms of three vitamin B_6,pyridoxine, pyridoxamine and pyridoxal, were prepared in crystalline forms as follows : Pyridoxine N-oxide was obtained by oxidation of pyridoxine base with hydroperoxide in glacial acetic acid. Pyridoxal N-oxide was prepared by oxidizing pyridoxine N-oxide with colloidal manganese dioxide and sulfuric acid. Oxidation of triacetyl derivative of pyridoxamine with hydroperoxide, followed by hydrolysis, yielded pyridoxamine N-oxide. These N-oxides easily returned to the natural forms of the vitamin with catalytic reduction.

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A cobamide coenzyme-dependent glycerol dehydratase was concomitantly produced with the well-known diol dehydratase in the cells of A. aerogenes ATCC 8724 grown anaerobically on a medium containing glycerol as a sole carbon source. The former enzyme was mainly included in the fraction of 0.2 to 0.4 (NH_4)_2SO_4 saturation, while the latter was predominantly precipitated by 0 to 20% (NH_4)_2SO_4 saturation. The optimum pH of the glycerol dehydratase was approximately 8.0 which was identical with that observed by Pawelkiewicz et al., using another strain of A. aerogenes and different from that of Lactobacillus species reported by Smiley・Sobolov. Its Km values for glycerol and DBC coenzyme were 0.85×10^<-3>M and 3.1×10^<-7>M, respectively. Glycerol served as a carbon source as well as an inducer for both the dehydratases under anaerobic conditions. On the other hand ethanediol and propanediol could not support the bacterial growth, despite of the facts that these compounds were metabolized to unidentified carbonyl compounds after being incorporated into the cells. On aerobic cultivation, all the three compounds were utilized for the growth of the bacteria through oxidative pathways, so could not act as inducers of the cobamide coenzyme dependent dehydratases.

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The author has found glutamine-ketoacids transaminase (GKT) activity in both the soluble and the mitochondrial fractions of rat liver and kidney. The liver enzymes were purified about 130 fold and GPT activity was not observed in the purified enzymes. The soluble GKT (GKTs) could be separated from the mitochondrial GKT (GKTM) by using zone electrophoresis and DEAE-cellulose column chromatography. The Km value of GKTM for glyoxylic acid was higher than that of GKTs. From these evidences described above, the GKT are considered to be isozymes each other which are localized in different compartment in the cells. The both purified isozymes had the highest specificity for glyoxylic acid. Some other ketoacids also could be amino acceptors for GKT, though they had a lower affinity than that of glyoxylic acid. They reacted with GKT as the following order : pyruvic acid > phenylpypuvic acid > α-ketobutyric acid > oxalacetic acid. The Km values of GKTs and GKTM for glutamine were 2.0×10^<-3>M and 2.2×10^<-3>M, respectively, and those for glyoxylic acid were 3.8× 10^<-3>M and 6.8×10^<-3>M, respectively, These GKT were strongly inhibited by isonicotinic acid hydrazide or hydroxylamine. Pyridoxal phosphate was partially resoluted from holo-GKT by dialysing against 10^<-3>M hydroxylamine solution and the resoluted GKT recovered its activity by the addition of pyridoxal phosphate.

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N. Katsunuma has studied GOT isozymes from the standpoint of differences in their intracellular distributions and metabolic roles. Since TCA-cycle enzymes and oxidative phosphorylation are almost exclusively localized in mitochondria, while glycolytic or gluconeogenic enzymes are present in the cytoplasm, it is tempting to consider that cytoplasmic transaminase may play an important role in regulation of the glycolysis-gluconeogenic system. The present paper is on the role of the GOTs in gluconeogenesis. To test this, experiments were made involving liver perfusion and L-penicillamine(L-PeA) was used as a selective inhibitor of GOTs. The results show that the additions of aspartic and α-ketoglutaric acids caused marked increase in the concentration of glucose in the circulating blood and in glycogen synthesis in the liver, but glucose and glycogen synthesis from both acids were inhibited by addition of L-PeA and glucose synthesis from oxalacetic acid was not affected by L-PeA. On the other hand, as we have already reported, when animals were placed on gluconeogenetic state, only GOTs was markedly induced, while no induction of GOTM was observed. Thus, in summary, it is clear from perfusion and induction experiments that GOTs is of importance for gluconeogensis involving glucose or glycogen production from certain amino acids.

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