Effect of nicotinic acid on the formation of catecholamine has been studied. Norepinephrine and dopamine concentrations in brain were 30 per cent higher and brain catecholamine formation was 50 per cent higher in the nicotinic acid-supplemented rats than the nicotinic acid-deficient rats. However, these catecholamine levels of the nicotinic acid-deficient rats were recovered by the administration of nicotinic acid. The concentration of brain tyrosine was unaltered after administration of nicotinic acid to the nicotinic acid-deficient rats. Therefore, the changes catecholamine formation by the nicotinic acid supplementation were not due to the difference of tyrosine concentration in the brain which is the precursor for catecholamine biosynthesis. As the difference of catecholamine concentration between the nicotinic acid deficient and the nicotinic acid supplemented group was smaller than that of catecholamine formation of these groups, the turnover of catecholamine was supposed to be decreased in nicotinic acid deficiency.

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1. Pyridoxal 5'-phosphate and pyridoxamine 5'-phosphate were effective for the association of apo-form II of ornithine amino transferase [EC 2. 6. 1. 13]; whereas other B6 derivatives, such as pyridoxal, pyridoxamine, pyridoxine and pyridoxine 5'-phosphate, had no effect on form II of this apoenzyme.
2. The pyridoxal 5'-phosphate contents of the native enzyme, and reconstituted forms I and II were determined by two different methods to be 1.5 moles, 2.5 moles and 3.3 moles of pyridoxal 5'-phosphate/mole of enzyme, respectively.

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Both glycine and methionine, when added to a suspension of human bone marrow cells, impaired the utilization of deoxyuridine for DNA synthesis, using either the uptake of ³H-deoxyuridine or the subsequent uptake of ³H-thymidine as an index. Homocysteine reduced the uptake of both 3H-deoxyuridine and ³H-thymidine, indicating interference with DNA synthesis after the stage of thymidylate synthesis. Another explanation that the decreased uptake of both substances by homocysteine was due to cell damage caused in vitro was suggested by the trypan blue viability test. Serine generally did not produce significant effects. No difference could be detected between the results in normoblastic and megaloblastic marrow.

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The effects of various sugars and sugar derivatives on flavinogenesis were examined using non-growing cells of a high flavinogenic mold, Ashbya gossypii. Glucose, fructose and galactose were found to be the most stimulative. Glycerol and glucono-δ-lactone were less stimulative; next in order were n-propanol, n-butanol, glycols and butanediols, which were likewise effective; acetate, lactate and pyruvate were slightly stimulative. In contrast, ribose, xylose, arabinose, ribitol, citrate, succinate, oxaloacetate, glyoxylate and malate were rather inhibitory, in additions at 1.0%. Among these compounds, ethanol (1%) greatly stimulated riboflavin formation.
Maximum flavinogenesis with the above stimulants was attained by the additions of 1% ethanol, 1.25-3.0% glucose, 1.25% glycerol, 4.0-6.0 propane and butanediols, 1.0% pyruvate and 0.9% acetate after 37 hr incubation, respectively. These compounds inhibited flavinogenesis with increasing concentrations above their optimum concentrations.
The stimulation effect of ethanol far exceeded those of other stimulants but ethanol had almost no effect on growth and pH values during incubation. With the addition of ethanol (1%) during incubation, maximum formation (1, 776, μg/g wet mycelia) of riboflavin was achieved when added at the start of incubation and the most effective utilization was observed when added at the logarithmic phase of flavinogenesis, although the maximum formation of riboflavin in the latter case was much lower than in the former case. The relation of sugar metabolism, especially ethanol metabolism, to flavinogenesis was discussed with the flavinogenic activities of these additives.

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(1) The effect of thiamine deficiency during pregnancy and lactation on lipogenesis in the brain of rat pups was determined.
(2) Acetate incorporation to brain lipids in thiamine-deficient rats in vivo was no less than in pair fed control rats, apart from slightly reduced fatty acid synthesis in the cerebrum.
(3) Glucose incorporation to brain lipids in vivo was considerably reduced in thiamine-deficient pups.
(4) The inducible NADP dependent malic enzyme activity was increased in thiamine-deficient pup brains.
(5) The synthesis of acetyl-CoA appears to be the rate limiting step in lipogenesis in thiamine-deficient pup brains.

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The addition of a trapping agent, glyoxal, to a non-growing cell medium with Eremothecium ashbyii brought about the accumulation of large quantities of a green fluorescent compound, with a simultaneous rigid inhibition of riboflavin formation. The fluorescent compound was isolated from the mycelia after non-growing cell incubation and highly purified to a crystalline form through various column chromatographic steps. The purified compound was identified as 8-ribityllumazine by comparison with a synthesized reference compound by means of spectro photometric and fluorometric measurements. Furthermore, it was verified that glyoxal, at the added concentration, and 8-ribityllumazine, at the accumulated concentration, caused slight inhibition of riboflavin formation with riboflavin synthetase from E, ashbyii. Accordingly, it was concluded that the 8-ribityllumazine accumulated is a derivative compound of an intermediate in flavinogenesis which is 4-ribitylamino 5-amino-2, 6-dihydroxypyrimidine based on the trapping action of glyoxal.

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The properties of thiamine diphosphatase (TDPase) and p-nitrophenylphosphatase (p-NPPase) in rat small intestine were investi gated. TDPase activity, like p-NPPase activity, was high in the mucosa and in the proximal region. Both activities were high in the membrane associated fractions of the duodenal mucosa. Furthermore, TDPase had the same properties as intestinal alkaline phosphatase (al-Pase). These results suggest that thiamine diphosphate (TDP) and p-nitrophenyl phosphate (p-NPP) are hydrolyzed by a single enzyme, al-Pase, in the intestine.

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1. Left atrial and papillary muscle isolated from rat heart were suspended in a Magnus' apparatus and influenced by thiamine tetrahydrofurfuryldisulfide (TTFD) added to the medium at concentra tions of from 5×10^-6 to 1.6×10^-4g/ml.
2. Contractile tension of left atrial and papillary muscle driven by electrical stimulation was respectively increased by 27.2 and 55.0% of each control under the most effective conditions at 60 min after addition. Most of the drug effect remained even after the drug removal from medium.
3. The refractory period of these muscles estimated using the modified method of Govier was increased by the drug: the maximum increase in atrial muscle was 106.3% while that in papillary muscle was 38.3% of each control. Most of the drug effect on papillary muscle remained after the drug removal from medium while the effect on left atrial muscle reduced to the similar degree to that seen in the papillary muscle.
4. Maximum driving frequency of left atrial muscle estimated using the modified method of Tanz was decreased by the drug concentrations higher than 4×10^-5g/ml and the drug effect remained after the drug removal from medium, while the drug effect on papillary muscle was slight at any drug concentration.
5. The drug thiamine used in place of TTFD little influenced the refractory period and the maximum driving frequency of these muscles at the drug concentrations of 10^-6 and 2×10g/ml.
6. From the results, the effect of TTFD as an antiarrhythmic was discussed.

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During the studies on a photoreaction of retinal, involving various kinds of (Z)-(E) isomerization, a heretofore unknown photo product of retinal was isolated in a pure state and was characterized unambiguously. Thus, direct irradiation of all-(E)-retinal (I) and of all-(E)-β-ionylidenecrotonaldehyde (II) in acetonitrile solution gave the corresponding 6e-electrocyclized photoproducts, (III) and (IV), both via the possible 7-(Z)-isomer intermediates of the parent conjugated poly enals. Unlike the lower members in the retinal series, it was also con firmed that sigmatropic rearrangement or photo-Diels-Alder reaction hardly proceeds in these higher members of the series mentioned above.

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This study was conducted to evaluate influences of dif ferent dietary fats and fatty acid on the lipid accumulation in the liver of growing rats fed low protein diets containing purified whole egg pro tein at 5 protein calories percent (PC%). Rats were fed for 2 (experi ment 1) or 3 (experiment 2) weeks. In experiment 1, rats fed low protein diets with 0.1% soybean oil accumulated more lipids in the liver than those fed a control (20 PC%) diet with 10% soybean oil. The excess accumulation of lipids tended to be inhibited by the further addition of 9.9% soybean oil and was inhibited by 9.9% linoleic acid. In experi ment 2, the lipid content in the liver of rats fed the low protein diet with 9.9% lard was lowered by substituting 9.9% soybean oil, safflower oil and linoleic acid for lard. However, even rats fed the low protein diet with linoleic acid accumulated still more lipids in the liver than those fed the control diet. Furthermore, the liver lipid level in rats fed low protein diets with 20% soybean oil was almost the same to that in rats fed the low protein diet with 10% soybean oil. From these results, the mecha nism of lipid accumulation in liver of the rat fed low protein diet was discussed.

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The effect of niacin deficiency on the activities of tyrosine hydroxylase and tryptophan-5-monooxygenase was studied in relation to the contents of catecholamines and serotonin in brain to clarify the role of the vitamin in brain function. Male rats 4 weeks of age were fed a niacin-free, low-protein diet for 3 weeks. Tests for the avoidance learn ing behavior were started at 14 th day in experimental period and were repeated 3 times every other day. After sacrifice on the 21st day, the activities of tyrosine hydroxylase and tryptophan-5-monooxygenase in the brain homogenates were assayed. In the other experiments, contents of dopamine, norepinephrine and serotonin in brain were determined in rats fed on the same niacin-deficient, low-protein diet for 3 weeks. The activity of crude tyrosine hydroxylase in brain was found to be increased significantly in niacin deficiency and was reduced below that of the control one week after niacin supplementation to the deficient rats. On the contrary, contents of dopamine and norepinephrine in whole brain of the niacin-deficient rats showed a significant decrease. No significant dif ference in brain tryptophan-5-monooxygenase activities was observed among niacin-deficient, low-protein control and normal commercial diet groups. Brain serotonin contents of the niacin-deficient animals were almost the same as that of the low-protein control, but were less than that of the rats fed on niacin-supplemented 20% casein diet. Though, no significant difference was observed between the learning abilities of niacin deficient and control groups, these results suggested that the change of catecholamine and serotonin metabolism in brain was one of the causes for some malfunction of the central nervous system induced by niacin deficiency.

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Nutritional effects of dietary nitrogen sources on rats subjected to 65% distal resection of the small bowel were compared at the 2.4% nitrogen level, i.e., by feeding the rats a diet which contains 2.4% nitrogen from various sources. The nitrogen sources used were casein (C), the casein-simulated amino acid mixture (F), the proposed amino acid mixture (T-2), which was devised in our laboratory, and the amino acid-casein mixture (R), in which 25% of the proposed amino acid mixture was replaced by isonitrogenous casein. All the experimental diets were made cellulose-free. Total weight gains of the resected groups during three weeks were less than those of the corresponding unresected groups because of the depressed gains in the first postoperative week. In the resected rats, as well as in the unresected rats, the maximum total weight gain was obtained with diet R and followed weight gains with diet C, diet F, and diet T-2. Fecal weight increased moderately in the resected rats but the degree of the increase was not influenced by the type of dietary nitrogen source. Dry weight of intestinal remnants in creased markedly within one week after resection. The extent of hyper plasia was not altered by the type of dietary nitrogen source. These results indicate that an amino acid mixture partially replaced with casein may be a useful dietary nitrogen source for short gut syndrome.

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Developmental changes in sucrase-isomaltase complex formation were investigated in intestinal mucosal homogenates and brush border membranes of 15-day-old, 18-day-old and adult rats using Sephadex G-200 column chromatography and polyacrylamide disc gel electrophoresis. Disaccharidases were solubilized by papain treatment. The molecular weight of the complex did not change during development, however, the activity ratio of sucrase to isomaltase increased during development. Furthermore, a significant amount of free isomaltase, which was probably not to be derived from intestinal brush border membrane, was detected before the weanling.

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In order to investigate the functions of reductones, their mutagenic action was studied with and without cupric ion using Salmonella typhimurium TA 100 strain. Triose reductone (TR), which has the simplest enediol structure among reductones, induced a notable frequency of his+ revertants at 2.5 or 5 mM. The addition of cupric ion to TR at a molar ratio of 1:1, 000 lowered the most active concentration of TR to 1mM. Another typical enediol reductone, ascorbic acid (AsA), had no detectable mutagenic action by itself. However, the treatment of the bacteria with a freshly mixed solution of 5mM AsA and 1 or 5 μM cupric ion exerted effective mutagenic action. The mutagenecity of these reductones, with or without cupric ion, occurred at a relatively narrow range of concentrations. Furthermore, the frequency induced by these reductones was extremely low compared with that by N-methyl-N' nitro-nitrosoguanidine or the mixture of AsA and cupric ion which was used by STICH et al. (STICH, H. F., KARIM, J., KOROPATONIC, J., and LO, L., Nature, 260, 722 (1976)). On the other hand, ascorbyl-3-phosphate, in which 3-OH groups of AsA was esterified with phosphate, had no effective mutagenic function even in the presence of cupric ion. These findings indicated that enediol structure in reductones played an essential role in the mutagenesis. The higher concentrations of reductones or the mixture with cupric ion seemed to cause the lethal effect on the bacteria. Control with or without cupric ion exerted no mutagenic action.

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A trypsin inhibitor was isolated from beans of Phaseolus vulgaris, cultivar. Kintoki, and the specific activity increased 200 times as high as that of the crude extract. It was homogeneous on several electrophoreses and the molecular weight was about 13, 000. The amino acid composition was characterized by high ratios of cystine, aspartic acid, and serine. It inhibited trypsin in a molar ratio of 1:1 and achymotrypsin in a molar ratio of 2:1. It, however, inhibited neither pepsin nor pronase. It was relatively stable to heat treatment in the acidic medium, but not in the alkaline medium. Neither pepsin nor pronase destroyed the inhibitory function.

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In studies on the cause of hypercholesterolemia in alloxan diabetic rats, the pool size and basal daily synthesis of conjugated bile salts were measured by the washout method and neutral sterols in the luminal contents were determined using cholestyramine. The results showed that in diabetic rats: 1) the biliary excretions of cholesterol and bile salts were significantly increased; 2) the pool size of conjugated bile salts was increased and its rate of synthesis was higher than in controls; 3) the amount of neutral sterols in the luminal contents doubled when cholesterol absorption was inhibited by administration of cholestyramine; 4) the amount of neutral sterols excreted in the feces was the same as in controls. Thus, it was concluded that hypercholesterolemia may be partly caused by an increased rate of intestinal absorption of cholesterol, derived mainly from sloughed off epithelial cells and bile, and due to facilitated micellar formation by the increased amount of bile salts in the intestine.

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