Document Detail


The role of the cytoplasmic redox potential in the control of fatty acid synthesis from glucose, pyruvate and lactate in white adipose tissue.
MedLine Citation:
PMID:  4313115     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The metabolism of lactate, pyruvate and glucose was studied in epididymal adipose tissue of starved, normally fed and starved-re-fed rats. Lactate conversion into fatty acid occurred at an appreciable rate only in the adipocyte of starved-re-fed animals. NNN'N'-Tetramethyl-p-phenylenediamine, an agent that transports reducing power from the cytoplasm to the mitochondria, caused large increments of fatty acid synthesis from lactate and a smaller one from glucose but a decrease in that from pyruvate. Glucose (1.0mm) increased fatty acid synthesis from lactate 4.3-fold but only 1.67-fold from pyruvate in adipocytes from normally fed animals. 2-Deoxyglucose decreased fatty acid synthesis from lactate to a greater degree (threefold) compared to that from pyruvate in adipocytes from starved-re-fed animals. l-Glycerol 3-phosphate contents were approximately equal in epididymal fat-pads, incubated in the presence of lactate or pyruvate, from normally fed animals, whereas the addition of 1mm-glucose resulted in a tenfold increase in l-glycerol 3-phosphate content only in the presence of lactate. The l-glycerol 3-phosphate content was tenfold higher in adipose tissue from starved-re-fed animals incubated in the presence of lactate than in the presence of pyruvate. 2-Deoxyglucose caused these values to be slightly lowered in the presence of lactate. We suggest that lactate metabolism is limited by the rate of NADH removal from the cytoplasm. In the starved-re-fed state, this occurs by reduction of dihydroxyacetone phosphate formed from glycogen to produce l-glycerol 3-phosphate, thus permitting lactate conversion into fatty acid. When glucose is the substrate, and rates of transport are not limiting, the rate of removal of cytoplasmic NADH limits glucose conversion into fatty acid.
Authors:
M L Halperin; B H Robinson
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  The Biochemical journal     Volume:  116     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  1970 Jan 
Date Detail:
Created Date:  1970-03-27     Completed Date:  1970-03-27     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  235-40     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adipose Tissue / metabolism*
Aniline Compounds / metabolism
Animals
Fatty Acids / biosynthesis*
Glucose / metabolism*
Glycerophosphates / analysis
Hexoses / metabolism
Lactates / metabolism*
Male
NAD / metabolism
Oxidation-Reduction*
Pyruvates / metabolism*
Rats
Starvation / metabolism
Chemical
Reg. No./Substance:
0/Aniline Compounds; 0/Fatty Acids; 0/Glycerophosphates; 0/Hexoses; 0/Lactates; 0/Pyruvates; 50-99-7/Glucose; 53-84-9/NAD
Comments/Corrections

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