| Human placental vitamin B6 (pyridoxal) transport: normal characteristics and effects of ethanol. | |
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MedLine Citation:
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PMID: 1621875 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The aims of this study were to define normal human placental transport of pyridoxal, an important form of vitamin B6 in pregnancy, and to determine the effect of short-term alcohol on this process. Our studies used the isolated single cotyledon from the term placenta. Pyridoxal crossed the human placenta readily in both directions, but the transfer was a little less than half that of antipyrine and was significantly greater in the direction of the fetus. Pyridoxine appeared to have a similar clearance from the maternal compartment as pyridoxal, but transport of intact pyridoxal 5'-phosphate was much smaller. There was no saturable transfer of pyridoxal, and it was not transferred from the maternal to fetal compartments against a concentration gradient. Placental concentration of pyridoxal exceeded both maternal and fetal perfusate pyridoxal concentrations, but this concentration was equal for both perfusion directions. These composite data are most suggestive of passive transport of pyridoxal across the placenta, binding of the vitamin in the placenta as an explanation for its concentration there, and greater phosphorylation of pyridoxal in the placenta when the compound is transferred in the fetal direction, possibly displacing pyridoxal from its binding sites and permitting its greater release into the fetal compartment. Alcohol, 400-250 mg/dl over 2.5 h, inhibited the transport of pyridoxal from the maternal to fetal compartments by approximately 42% (P = 0.03) and resulted in a lower transfer of pyridoxal 5'-phosphate into the fetal perfusate (P = 0.02). |
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Authors:
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S Schenker; R F Johnson; J D Mahuren; G I Henderson; S P Coburn |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 262 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1992 Jun |
Date Detail:
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Created Date: 1992-08-04 Completed Date: 1992-08-04 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: R966-74 Citation Subset: IM |
Affiliation:
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Department of Medicine, University of Texas Health Science Center, San Antonio 78284-7878. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Biological Transport
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drug effects Biological Transport, Active / drug effects Ethanol / pharmacology* Female Humans Maternal-Fetal Exchange Mathematics Osmolar Concentration Placenta / metabolism* Pregnancy Pyridoxal Phosphate / metabolism Pyridoxine / antagonists & inhibitors, pharmacokinetics* |
| Grant Support | |
ID/Acronym/Agency:
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R01-AA-07514-05/AA/NIAAA NIH HHS |
| Chemical | |
Reg. No./Substance:
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54-47-7/Pyridoxal Phosphate; 64-17-5/Ethanol; 65-23-6/Pyridoxine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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