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Volume 24, Issue 1
Displaying 1-6 of 6 articles from this issue
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Toshihide KAJIWARA, Makoto MATSUDA1978 Volume 24 Issue 1 Pages 1-7
Published: 1978
Released on J-STAGE: April 28, 2009
JOURNAL FREE ACCESSThe antivitamin B6 effect of DL- and D-penicillamine has been studied in rats. A considerable elevation in the urinary excretion of vitamin B6 activity (pyridoxal and its thiazolidine derivative) has been shown as a parameter of B6 antagonism. Both DL- and D-penicillamine have been shown to have an antivitamin B6 effect in rats, although that induced by the DL-form is considerably greater, as would be expected from previous studies. We suggest that B6 supplementation should be included in any long term penicillamine therapy, regardless of the isomer that is employed.View full abstractDownload PDF (873K) -
Mayumi SATO, Luigi M. DELUCA, Yasutoshi MUTOI1978 Volume 24 Issue 1 Pages 9-23
Published: 1978
Released on J-STAGE: April 28, 2009
JOURNAL FREE ACCESSStudies were conducted to investigate the in vivo and in vitro effects of retinol and retinoic acid on the synthesis of mannolipids and mannopeptides in rat liver.
The incorporation of 14C-mannose into glycolipids and glycoproteins showed a decrease in vitamin A-depleted rats as compared with vitamin A-fed rats. By means of DEAE-cellulose, silicic acid and thin-layer chromatography, the mannose-containing lipids were separated into mannosyl retinyl phosphate (MRP, Rf 0.2) and dolichyl mannosyl phosphate (DMP, Rf 0.4), respectively. A rapid increase in the synthesis of labelled MRP was observed, exhibiting a peak between 25 and 60 min after intraperitoneal administration of retinol to vitamin A-depleted rats. Similarly, administration of retinoic acid brought about elevation of 14C mannolipid (Rf 0.2) synthesis with a peak at 60 min after injection. On the other hand, the incorporation of 14C-mannose into DMP (Rf 0.4) remained unchanged by such treatment. In vitro addition of retinyl phosphate, but not retinoyl phosphate, markedly stimulated the synthesis of 14C-mannolipid (Rf 0.2), using crude membrane of rat liver and GDP 14C-mannose as the donor. These findings strongly suggest that not only retinol but also retinoic acid plays an important biological role in man nosyl transfer reaction in rat liver. However, the molecular participation of a metabolity of retinoic acid in the formation of a mannolipid and the structure of such a metabokite remain to be established.View full abstractDownload PDF (1915K) -
METABOLISM OF FATTY ACIDS AND THE LEVELS OF KETONE BODIES IN THE LIVERS OF PYRIDOXINE-DEFICIENT RATSShuzo GOMIKAWA, Mitsuko OKADA1978 Volume 24 Issue 1 Pages 25-34
Published: 1978
Released on J-STAGE: June 15, 2009
JOURNAL FREE ACCESSLipid metabolism was examined in rats fed a high-protein pyridoxine-deficient diet, and their livers were found to contain large amounts of lipids, mainly in the forms of triglycerides and cholesteryl ester. The contents of ketone bodies in the livers of pyridoxine-deficient and the control rats were similar. Their NAD+/NADH ratios, calcu lated from the amounts of ketone bodies, were also similar in pyridoxine deficient and control groups when the animals were fed, but the ratio in pyridoxine-deficient rats was lower than that of control rats when the animals were starved. After injection of 14C-linoleic acid, the amounts of expired 14CO2 in pyridoxine-deficient and control rats were similar. The pattern of incorporations of 14C-linoleic acid into various lipid components of the livers were examined; incorporation into the phospho lipid fraction was similar in control and deficient rats, but the incorpora tion into the triglyceride fraction was slower, and the incorporation into cholesterol was faster in deficient animals than in controls.View full abstractDownload PDF (1062K) -
Hisateru MITSUDA, Kenji NAKAJIMA, Yoshiyukl NISHIKAWA1978 Volume 24 Issue 1 Pages 35-46
Published: 1978
Released on J-STAGE: April 28, 2009
JOURNAL FREE ACCESSThe present experiments were carried out to investigate the relation between sugar metabolism and riboflavin formation in nongrowing cells of Eremothecium ashbyii incubated with various sugars (related compounds) and purines.
Glycerol, gluconate and glucono-o-lactone markedly stimulated riboflavin formation with increasing concentrations up to 0.5% or with increasing incubation times, but above the concentration range the effects of these substances on flavinogenesis were different. Ribose, xylose and ribitol brought about a weak stimulation of riboflavin formation in a concentration range of 0-0.2%. Glucose and fructose enhanced flavinogenesis in a concentration range of 0-0.5% but were inhibitory above the range. Glucosamine strongly restricted riboflavin formation in lower concentrations and the inhibition effect occurred immediately after its addition. The inhibition of riboflavin formation due to glucosamine (0.15%) was almost completely recovered by glucose (1.0%) but not by glycerol. Caffeine (5mM) reduced the yields of riboflavin to a fairly greater extent. The decrease was reversed not by xanthine, guanine and theobromine but by glycerol, ribose and glucose, especially by glycerol (0.5%). Accordingly, caffeine was considered to inhibit a pentose phosphate pathway and glucosamine to inhibit a glycolytic pathway closely related to flavinogenesis.View full abstractDownload PDF (1536K) -
Toshio OKANO, Mitsue YASUMURA, Kumiko MIZUNO, Tadashi KOBAYASHI1978 Volume 24 Issue 1 Pages 47-56
Published: 1978
Released on J-STAGE: April 28, 2009
JOURNAL FREE ACCESSIn order to confirm the photochemical conversion of 7-dehydrocholesterol (7-DHC) into vitamin D3 in rat skin, the following in vitro and in vivo experiments were carried out. In the first (in vitro) experiment, the skin stripped off from a sacrificed normal rat was irradiated with an ultraviolet (UV) lamp for a constant period. In the second (in vivo) experiment, the normal rat, irradiated under the same condition mentioned above, was sacrificed and then the skin was stripped off. Lipids were individually extracted with chloroform-methanol (1:1) from the skin obtained in the two experiments and the solvent was evaporated. The resulting residue was saponified and the unsaponifiable matter extracted with benzene was purified by application to hydroxyalkoxypropyl (HAP) Sephadex column chromatography. The resulting purified vitamin D3 fraction was applied to high-performance liquid chromatography (HPLC) in order to estimate vitamin D3. No peak, aside from that of α-naphthol as an internal standard, was observed in the HPLC chromatogram on the skin obtained from the non-irradiated rat, whereas the peak corresponding to vitamin D3 was observed in each HPLC chromatogram on both the irradiated skin (in vitro experiment) and the skin obtained from the irradiated rat (in vivo experiment). The peaks, confirmed to be due to vitamin D3 by the results of co-chromatography, were increased according to the increase of irradiation energy and there were little differences between the corresponding estimated values of vitamin D3 in the two experiments. These results prompted the conclusion that 7-DHC in rat skin was photochemically converted into vitamin D3 by UV irradiation and that the in vivo vonversion mechanism might be the same as the in vitro one.View full abstractDownload PDF (1043K) -
Sueko SAGAWA, Keizo SHIRAKI1978 Volume 24 Issue 1 Pages 57-65
Published: 1978
Released on J-STAGE: April 28, 2009
JOURNAL FREE ACCESSThe causes of osmotic fragility of red cells were studied in rats. Osmotic fragility of red cells in vivo changed after removal of the spleen or induction of experimental splenomegaly by repeated intraperitoneal injections of methyl cellulose (MC): in splenectomized rats, the red cells showed reduced osmotic fragility and an increase in diameter as well as in contents of phospholipids and cholesterol. Conversely in rats with splenomegaly, the cells showed increased osmotic fragility and a decrease in diameter and in lipid contents.
Results confirmed that increase in the phospholipid content resulted in decreased fragility and that increase in the cholesterol content brought about decreased spherocytosis. The activity of lecithin cholesterol acyltransferase (LCAT) in the plasma varied inversely with the cholesterol content of the red cells.
The above results show that the fragility of red cells is influenced by their lipid content and shape, and that LCAT activity in the plasma influences the membrane content of cholesterol and spherocytosis.View full abstractDownload PDF (972K)
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