13C NMR studies of glycogen turnover in the perfused rat liver

G. I. Shulman, D. L. Rothman, Youngran Chung, L. Rossetti, W. A. Petit, E. J. Barrett, R. G. Shulman

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

To assess whether hepatic glycogen is actively turning over under conditions which promote net glycogen synthesis we perfused livers from 24-h fasted rats with 20 mM D-[1-13C]glucose, 10 mM L-[3-13C]alanine, 10 mM L-[3-13C]lactate, and 1 μM insulin for 90 min followed by a 75-min 'chase' period with perfusate of the same composition containing either 13C-enriched or unlabeled substrates. The peak height of the C-1 resonance of the glucosyl subunits in glycogen was monitored, in real time, using 13C NMR techniques. During the initial 90 min the peak height of the C-1 resonance of glycogen increased at almost a constant rate reflecting a near linear increase in net glycogen synthesis, which persisted for a further 75 min if 13C-enriched substrates were present during the 'chase' period. However, when the perfusate was switched to the unenriched substrates, the peak height of the C-1 resonance of glycogen declined in a nearly linear manner reflecting active glycogenolysis during a time of net glycogen synthesis. By comparing the slopes of the curve describing the time course of the net [1-13C]glucose incorporation into glycogen with the rate of net loss of 13C label from the C-1 resonance of glycogen during the 'chase' period we estimated the relative rate of glycogen breakdown to be 60% of the net glycogen synthetic rate. Whether this same phenomenon occurs to such an appreciable extent in vivo remains to be determined.

Original languageEnglish (US)
Pages (from-to)5027-5029
Number of pages3
JournalJournal of Biological Chemistry
Volume263
Issue number11
StatePublished - 1988
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of '<sup>13</sup>C NMR studies of glycogen turnover in the perfused rat liver'. Together they form a unique fingerprint.

  • Cite this

    Shulman, G. I., Rothman, D. L., Chung, Y., Rossetti, L., Petit, W. A., Barrett, E. J., & Shulman, R. G. (1988). 13C NMR studies of glycogen turnover in the perfused rat liver. Journal of Biological Chemistry, 263(11), 5027-5029.