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T Akino

Publications and source records attributed to T Akino.

At least 163 records · Page 9Linked to original sources
PubMed1978

Changes in the structural and metabolic heterogeneity of phosphatidylcholines in the developing rat lung.

In the present study the developmental profiles of the structural and metabolic heterogeneity of rat lung phosphatidylcholine are presented. The individual molecular species of phosphatidylcholine at different stages of the developing rat lung were analyzed as diacylglycerol derivatives. The metabolic heterogeneity of rat lung phosphatidylcholine was also studied by incubation using lung slices with radioactive precursors. The results obtained were as follows: 1. A significant increase of lung phosphatidylcholine during perinatal development (up to 1 day after birth) was found to be largely due to the increase of dipalmitoyl species. The percentage of palmitoyl-palmitoleoyl species also increased from --4 to --1 day of gestation, while palmitoyl-oleoyl species were found to decrease during development. Other molecular species showed no significant changes. 2. The incorporation of [1-14C]palmitoyl lysophosphatidylcholine into saturated phosphatidylcholine was relatively low at the earlier stage of fetal development, but it increased significantly in the last stage and reached its maximum at one day prior to birth and one day prior to the marked accumulation of dipalmitoylphosphatidylcholine occurring in the lung. In contrast, the incorporation of [3H]glycerol into saturated phosphatidylcholine remained, without showing a marked alteration during development. These results suggest that the lysophosphatidylcholine pathway which is mainly attributed to transacylation mechanism between 2 molecules of lysophosphatidylcholine may contribute to the marked production of dipalmitoylphosphatidylcholine in the lung in the last stage of gestation.

Aging↗
PubMed1978

Comparison of molecular structure of glycerolipids in rat lung.

The major individual molecular species of glycerolipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and diacylglycerol of rat lung were determined quantitatively as diacylglycerol acetates. 1. In three glycerolipids such as phosphatidylcholine, phosphatidylglycerol and diacylglycerol, the main molecular species was dipalmitoyl. The species was not detectable in phosphatidylethanolamine and was not of quantitative importance in phosphatidylinositol. 2. The oligoenoic molecular species in phosphatidylethanolamine and phosphatidylinositol contained palmitoyl and stearoyl species in almost equal amounts, while those of phosphatidylcholine, phosphatidylglycerol and diacylglycerol were principally of the palmitoyl types. 3. Tetraenoic species of phosphatidylinositol and diacyl types of phosphatidylethanolamine were predominantly of stearoyl types. Tetraenoic diacylglycerol also contained significant amounts of stearoyl-arachidonyl species. The value was about 3-fold that of palmitoyl-arachidonyl species. However, palmitoyl types were rather higher in phosphatidylcholine and phosphatidylglycerol. 4. The alkenyl-acyl types of lung phosphatidylethanolamine consisted predominantly of polyenoic species, namely, tetraenoic, pentaenoic and hexaenoic species. The pentaenoic and hexaenoic species of all glycerolipids examined consisted mainly of palmitoyl types.

Animals↗
PubMed1978

Metabolism of lecithin and phosphatidylglycerol in surfactant fraction of the lung.

The metabolisms of lecithin and phosphatidylglycerol in the surfactant and residual fractions of rat lung were compared using the in vitro system where tissue slices and radioactive precursors such as [14C]palmitic acid, [14C]palmitoyl lysolecithin and [14C]stearoly lysolecithin were inculbated. The incorporation of precursors into the residual lecithin proceeded linearly during the incubation time, while the time curve on the incorporation into the surfactant lecithin exhibited a lag period before the incorporation increased significantly. A similar tendency was also observed in the incorporation into phosphatidylglycerol. These findings suggested a precursor-product relationship between the corresponding lipids in both the fractions. The turnover time of lecithin was approx. 340-370 min and that of phosphatidylglycerol was 118 min in the intracellular surfactant fraction. The turnover rates of lecithin and phosphatidlyglycerol were approx. 0.6 and 2 nmoles/g of wet tissue, respectively. The transfer of lecithin from the residual fraction to the surfactant fraction was hardly influenced by the difference of fatty acid moiety at the 2-position of 1-palmitoly-lysolecithin. However, the turnover time of 1-palmitoyl lecithin (360 min) was distinctly shorter than that of 1-stearoly species (730 min). The turnover time of the saturated lecithin was also shown to be 328 min. On the other hand, polyenoic species showed the shorter turnover time; 182 min for the tetraenoic species.

Animals↗
PubMed1978

Alveolar phospholipids in pulmonary alveolar proteinosis.

The biochemical compositions of lung lavage fluid from three patients and that of the lung tissue obtained by a biopsy from a patient with alveolar proteinosis were analyzed. The lung lavage fluid was separated to the supernatant and the insoluble precipitate fractions by a brief centrifugation and the lung tissue was separated to surfactant and residual fractions by sucrose density gradient centrifugation. The supernatant of lung washing contained larger quantities of protein and less lipid which was mainly composed of lecithin and sphingomyelin. In contrast, the insoluble material of lung washing contained 4--8 fold of lipid as compared with the supernatant, and lecithin was a predominant phospholipid. From the analysis of fatty acid and individual molecular species of major phospholipids, the higher contents of dipalmitoyllecithin and sphingomyelin containing palmitate were found in the insoluble material. The phospholipid composition and fatty acid composition of lecithin were similar between the precipitate fraction of lung washing and the surfactant fraction of lung tissue. The ratio of protein to phospholipid in the precipitate fraction was similar to that of lung washing. These analytical data suggest that the materials accumulated in the alveoli of the patients may be derived mainly from the lung surfactant fraction. The metabolic studies showed that lecithin synthesis through de novo and lysolecithin pathways works in human lung with this disease as actively as in rat lung. The secretion of lung lecithin to the surfactant fraction also appeared to be normal. From these analytical and metabolic findings, the causes for the accumulation of the materials which cover alveolar surface and impair gaseous exchange in the alveoli of pulmonary alveolar proteinosis, were discussed.

Animals↗
PubMed1977

Molecular composition of lecithins in the primary hepatoma induced by 3'-methyl-4-dimethylaminoazobenzene.

The lecithins of the primary hepatoma induced by 3'-methyl-4-dimethylaminoazobenzene (DAB) and host liver of rat were isolated, and the individual molecular species were estimated quantitatively by combined thin-layer and gaschromatographic analysis and specific enzymic hydrolysis. The DAB-hepatoma lecithins appeared to have more specific positioning of fatty acids than the transplanted hepatoma lecithins which have been reported by Dyatlovitskaya et al. (1974). However, there were some striking differences to be noted between the DAB-hepatoma and host liver lecithins. The usual type of molecular species of lecithin, saturated-unsaturated species, was the main component in the hepatoma and host liver. The amounts of the unusual species having impaired positional specificity in fatty acid such as the saturated-saturated and the unsaturated-saturated species were high in the DAB-hepatoma when compared with host liver, although the content of the unsaturated-unsaturated species of lecithin were almost similar in both the tissues. The formation of the unusual species of lecithin in tumor tissues was discussed in relation to the impairing in the enzyme systems involved in lecithin synthesis.

Animals↗
PubMed1976

Sphingolipid base metabolism. Stereospecific uptake of proton in the enzymatic conversion of sphinganine 1-phosphate to ethanolamine 1-phosphate.

D-erythro-(2S, 3R)-Sphinganine 1-phosphate was incubated with rat liver microsomes in the presence of tritiated water. [3H]Ethanolamine 1-phosphate was isolated and converted, through a combination of enzymatic and chemical reactions, to [3H]glycine. The labeled glycine was incubated with D-amino acid oxidase, an enzyme which, in the catalysis of the conversion of glycine to glyoxylic acid, specifically removes the hydrogen in the S configuration at carbon atom 2 of glycine. Essentially complete retention of the labeled hydrogen occurred upon conversion to glyoxylic acid. The combined results indicate that the conversion of D-erythro-(2S,3R)-sphinganine 1-phosphate to palmitaldehyde and ethanolamine 1-phosphate, catalyzed by sphinganine-1-phosphate lyase of rat liver microsomes, proceeds with the stereospecific incorporation of 1 atom of solvent hydrogen into the R configuration of ethanolamine 1-phosphate.

Animals↗
PubMed1976

Further study on the turnover calculation of lung lecithins.

Using the data reported previously by Moriya and Kanoh, the metabolic turnover of rat lung lecithins was calculated on the basis of the new assumption that the formation rate (Va) of lecithins from diacylglycerols did not equal the disappearance rate (Vb) of lecithins because of the presence of precursors other than diacylglycerols. The ratio of Va/Vb was almost the same in dienoic lecithin as that for total lecithins, whereas a very low ratio was found in saturated and hexaenoic species. The turnover time of lung lecithins estimated was markedly shorter than those determined in much later experimental periods after administration of labeled precursors. The reason for this discrepancy was discussed.

Animals↗
PubMed1975

Metabolic heterogeneity of lecithins in intestine.

The incorporation of [2-3H]glycerol and lysolecithin labeled with [2-3H]glycerol into lecithin and its subspecies was investigated in epithelial and muscular layers of rat small intestine. The labeled compounds were administered in two wways: the intraduodenal injection and the injection into femoral vein. The incorporation of glycerol into lecithin was distinctly higher in epithelial layer than in muscular layer in both administration routes, but the incorporation of lysolecithin into lecithin showed no marked differences between both layers. Among lecithin species, dienoic and monoenoic species were highly labeled with the injection of labeled glycerol, and dienoic as well as tetraenoic specied were markedly labeled with the injecttion of labeled lysolecithin. Anyhow, no marked differences were found on the incorporation pattern of any labeled compounds into lecithin between both layers and between both administration routes.

Animals↗