Linked Life Data

3123491

Source:http://linkedlifedata.com/resource/pubmed/id/3123491

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1988-3-23
pubmed:abstractText
Using 13C and 1H NMR we measured the rate of glycogen synthesis (0.23 +/- 0.10 mumol/min gram wet weight tissue (gww) in rat heart in vivo during an intravenous infusion of D-[1-13C]glucose and insulin. Glycogen was observed within 10 min of starting and increased linearly throughout a 50-min infusion. This compared closely with the average activity of glycogen synthase I (0.22 +/- 0.03 mumol/min gww) measured at physiologic concentrations of UDP-glucose (92 microM) and glucose-6-phosphate (110 microM). When unlabeled glycogen replaced D-[1-13C]glucose in the infusate after 50 min the D-[1-13C]glycogen signal remained stable for another 60 min, indicating that no turnover of the newly synthesized glycogen had occurred. Despite this phosphorylase a activity in heart extracts from rats given a 1 h glucose and insulin infusion (3.8 +/- 2.4 mumol/min gww) greatly exceeded the total synthase activity and if active in vivo should promote glycogenolysis. We conclude that during glucose and insulin infusion in the rat: (a) the absolute rate of myocardial glycogen synthesis can be measured in vivo by NMR; (b) glycogen synthase I can account for the observed rates of heart glycogen synthesis; (c) there is no futile cycling of glucose in and out of heart glycogen; and (d) the activity of phosphorylase a measured in tissue extracts is not reflected in vivo. These studies raise the question whether significant regulation of phosphorylase a activity in vivo is mediated by factors in addition to its phosphorylation state.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
263
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2285-91
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
NMR measurements of in vivo myocardial glycogen metabolism.
pubmed:affiliation
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.