Linked Life Data

478182

Source:http://linkedlifedata.com/resource/pubmed/id/478182

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1979-11-29
pubmed:abstractText
An "endoneurial" preparation from a rabbit tibial nerve fascicle was used to study the ability of peripheral nerve axons and Schwann cells to derive their composite energy requirements from glucose, D-beta-hydroxybutyrate, or albumin-bound palmitate, and the effects of insulin in vitro on their composite glucose utilization. Samples incubated with 5 mM glucose for 2 h maintained a stable O2 uptake and P-creatine and ATP concentrations, and they exhibited a slight increase in P-creatine/creatine ratio (the electron microscopic appearance of the preparation was previously shown to be unaltered under these conditions). The rate of glucose oxidation required to account for the O2 uptake accounted for 61% of the glucose uptake. In samples incubated without substrate for 2 h, a marked fall in tissue glucose was associated with a 50% decrease in O2 uptake and with decreases in P-creatine, ATP, and in the P-creatine/creating ratio. In medium lacking glucose but containing 5 mM DL-beta-hydroxybutyrate, a stable rate of D-beta-hydroxybutyrate uptake was observed, and acetoacetate production accounted for only a small fraction; significant decreases in O2 uptake or ATP were prevented, and, although P-creatinde and the P-creatine/creatine ratio fell, they remained significantly higher than after incubation without substrate. An efficient blood-nerve barrier to albumin is known to exist. Medium containing albumin-bound palmitate with molar ratios or palmitate/albumin of 1 or 2 (highest FFA concentration, 1.32 meq/L) failed to prevent decreases in P-creatine, ATP, and in the P-creatine/creatine ratio during incubations without glucose; the associated O2 uptakes suggested that the tissue is susceptible to respiratory uncoupling and depression son exposure to albumin-blund palmitate as compared with non-neural tissue. Insulin (100 or 1000 microU/ml) had no detectable effects on glucose utilization in the endoneurial preparation during 2-h incubations with 5 mM glucose or (U-14C) glucose. In contrast, in epineurial tissue from rabbit sciatic nerve, insulin (100 micronU/ml) increased (U-14C) glucose incorporation into CO2 and total lipid. The neural components of peripheral nerve are probably dependent on glucose as their major substrate for energy production and respiration under most physiologic conditions in which elevated plasma ketone body concentrations are absent; their composite glucose utilization is not subject to acute, direct regulation by insulin in concentrations that might reasonably be derived from plasma insulin of pancreatic origin.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0012-1797
pubmed:author
pubmed:issnType
Print
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
878-87
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
In vitro studies of the substrates for energy production and the effects of insulin on glucose utilization in the neural components of peripheral nerve.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.