Document Detail

Placental formation of lactate from transferred L-alanine and its impairment by aminooxyacetate in the late-pregnant rat.
MedLine Citation:
PMID:  4016148     Owner:  NLM     Status:  MEDLINE    
After 20 min infusion of L-[U-14C]alanine through the left uterine artery in 21-day-pregnant rats, the radioactivity in the plasma of fetuses from the left uterine horn was much higher than in their mothers and was composed of approximately equal parts of [14C]alanine and [14C]lactate, with a minor percentage of [14C]glucose. Radioactivity in fetal plasma was much lower when the mothers were infused with alpha-amino[14C]isobutyric acid. The simultaneous infusion of aminooxyacetate decreased materno-fetal transfer of radioactivity from [14C]alanine but not from alpha-amino[14C]isobutyric acid, and this effect corresponded to a complete disappearance of the [14C]lactate in fetal plasma without affecting [14C]alanine levels or alanine concentration in the fetuses. Placenta slices in vitro metabolized L-[U-14C]alanine into [14C]lactate and 14CO2 at the rate of 7 nmol/g per min, and this process was inhibited by the presence of 1 mM aminooxyacetate in the medium. Placental uptake of alpha-amino[14C]isobutyric acid was half that of [U-14C]alanine, and aminooxyacetate did not affect this parameter with either of the labelled compounds. Results indicate that the lower transfer to the rat fetus of the 14C atoms from alpha-amino[14C]isobutyric acid as compared to that from [14C]alanine is due not only to the diminished placental carrier system of the former but also to its non-metabolyzable condition. It is proposed that the capacity of the placenta to metabolyze L-alanine to lactate and the subsequent release of lactate to the fetus constitute important factors for the fetal metabolic economy.
M Palaćin; M A Lasunción; R M del Rio; E Herrera
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  841     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1985 Jul 
Date Detail:
Created Date:  1985-09-06     Completed Date:  1985-09-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  90-6     Citation Subset:  IM    
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MeSH Terms
Acetic Acids / pharmacology*
Alanine / metabolism*
Aminoisobutyric Acids / metabolism
Aminooxyacetic Acid / pharmacology*
Lactates / biosynthesis*
Lactic Acid
Maternal-Fetal Exchange
Placenta / metabolism*
Pregnancy, Animal*
Rats, Inbred Strains
Reg. No./Substance:
0/Acetic Acids; 0/Aminoisobutyric Acids; 0/Lactates; 50-21-5/Lactic Acid; 56-41-7/Alanine; 62-57-7/2-aminoisobutyric acid; 645-88-5/Aminooxyacetic Acid

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