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L Lichtenberg

Publications and source records attributed to L Lichtenberg.

8 recordsLinked to original sources

Effects of glucose oligomers on the glycogen levels of isolated hepatocytes.

Isolated rat hepatocytes appear able to utilize glucose oligomers of the maltose series for the synthesis of glycogen. This utilization is expressed as a stabilization of the glycogen levels during incubation, and also as an incorporation of 14C into glycogen from 14C-labeled glucose polymers. The extent of utilization is only a fraction of that observed with glucose, and it does not appear to be affected by insulin. No extracellular hydrolysis of the polymers seems to be required prior to their uptake by the isolated hepatocytes.

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Effects of isoproterenol treatment of isolated perfused rat hearts on myofibrillar phosphorylation and ATPase activity.

Perfusion of isolated rat hearts with isoproterenol resulted in increases in the level of protein-bound phosphate of the myofibrils. After perfusion of the hearts with 32P, followed by SDS-polyacrylamide gel electrophoresis of the purified myofibrils, four major 32P-containing protein bands were identified. Most of the increased 32P incorporation produced by isoproterenol was localized on the troponin I and myosin light chain bands, and, to lesser extent, on the M-protein band. ATPase activity was tested in the purified myofibrils. No changes in Ca2+ requirement for activation were found after isoproterenol perfusion. However, maximal ATPase activity was markedly reduced in the myofibrils obtained from isoproterenol-treated hearts. It would appear that the myofibrillar protein phosphorylation induced by isoproterenol perfusion results in a decrease in actomyosin ATPase activity.

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