Document Detail


Relationship of fetal alanine uptake and placental alanine metabolism to maternal plasma alanine concentration.
MedLine Citation:
PMID:  9843735     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Uterine and umbilical uptakes of alanine (Ala) were measured in 10 ewes before (control) and during intravenous infusion of Ala, which increased maternal arterial Ala concentration from 115 +/- 14 to 629 +/- 78 microM (P < 0.001). In 8 of these ewes, placental Ala fluxes were traced by constant intravenous infusion of L-[3,3,3-2H3]Ala in the mother and L-[1-13C]Ala in the fetus. Rates are reported as micromoles per minute per kilogram fetus. Ala infusion increased uterine uptake (2.5 +/- 0.6 to 15.6 +/- 3.1, P < 0.001), umbilical uptake (3.1 +/- 0.5 to 6.9 +/- 0.8, P < 0.001), and net uteroplacental utilization (-0.7 +/- 0.8 to 8.6 +/- 2.7, P < 0.01) of Ala. Control Ala flux to fetus from mother (Rf,m) was much less than the Ala flux to fetus from placenta (Rf,p) (0.17 +/- 0.04 vs. 5. 0 +/- 0.6). Two additional studies utilizing L-[U-13C]Ala as the maternal tracer confirmed the small relative contribution of Rf,m to Rf,p. During maternal Ala infusion, Rf,m increased significantly (P < 0.02) but remained a small fraction of Rf,p (0.71 +/- 0.2 vs. 7.3 +/- 1.3). We conclude that maternal Ala entering the placenta is metabolized and exchanged for placental Ala, so that most of the Ala delivered to the fetus is produced within the placenta. An increase in maternal Ala concentration increases placental Ala utilization and the fetal uptake of both maternal and placental Ala.
Authors:
M Timmerman; M Chung; R B Wilkening; P V Fennessey; F C Battaglia; G Meschia
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  275     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Dec 
Date Detail:
Created Date:  1999-02-03     Completed Date:  1999-02-03     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  E942-50     Citation Subset:  IM    
Affiliation:
Department of Obstetrics and Gynecology, Erasmus University, Rotterdam, The Netherlands 3000 DR.
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MeSH Terms
Descriptor/Qualifier:
Alanine / blood*,  pharmacokinetics*
Amino Acids / blood,  metabolism
Animals
Female
Fetal Blood / metabolism
Fetus / metabolism*
Osmolar Concentration
Placenta / metabolism*
Pregnancy
Pregnancy, Animal / blood*
Sheep / embryology
Umbilical Cord / metabolism
Grant Support
ID/Acronym/Agency:
P50 HD-20761/HD/NICHD NIH HHS; R01 HD-29188/HD/NICHD NIH HHS
Chemical
Reg. No./Substance:
0/Amino Acids; 56-41-7/Alanine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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