Sedoheptulose-1,7-diphosphate as a source of pentose phosphates in heart muscle]

A possibility and some peculiarities of phosphatase degradation of sedoheptulose-1,7-diphosphate in the myocardium has been demonstrated. The reaction products are inorganic phosphate and sedoheptulose-7-phosphate; the latter product is the substrate of the transketolase reaction during pentose phosphates production. The process is largely localized in the soluble fraction of heart cells; in cellular organelles it is represented in a lesser degree. Possible regulatory mechanisms of pentose phosphate biosynthesis in animal tissues are discussed.     

Membrane lipids of brush border of the rat small intestine as affected by ionizing radiation]

It was established that single total X-ray irradiation in the doses of 0.1; 0.4; 1.0; 2.0; 3.0 and 6.0 Gy 24 hours after irradiation results in reliable changes in membrane lipids composition of brush border of enterocytes in doses over 1.0 Gy. By this changes under increase of dosage of irradiation it were marked differences in comparison with control in lipid-protein, total phospholipids-protein, cholesterol-protein and cholesterol-total phospholipids rations. In lipid composition major changes are connected with increase of lysophosphatidylcholine and lysophosphatidylethanolamine concentrations, decrease of sphingomyelin content and increase of that of phosphatidylethanolamine. Content of cholesterol and free fatty acids decreased reliably under irradiation in doses over 1.0 Gy as well. Data obtained proves that structural-functional properties of brush border membranes of enterocytes of small intestine are altered under irradiation in doses ranging from 1.0 to 6.0 Gy. Lower doses (0.1; 0.4) cause only trend of changes named above.