Kinetiek en teratogeniteit van vitamine A. Een literatuurstudie

2.50
Hdl Handle:
http://hdl.handle.net/10029/260875
Title:
Kinetiek en teratogeniteit van vitamine A. Een literatuurstudie
Authors:
Olling M; Bode W; Bruil M; Groen K; Piersma AH
Other Titles:
Kinetics and teratogenicity of vitamin A. A literature study
Abstract:
This report describes a literature study of the kinetics of vitamin A in different animal species. The goal of this study was to collect data to develop a model for risk assessment of the teratogenic effects of vitamin A. In the diet vitamin A is present as esters of retinol and as carotenoids. In the gastro-intestinal tract the retinylesters are hydrolysed and the retinol formed are absorbed by the enterocytes in the lumen of the intestine. In the enterocytes esterification of retinol takes place and these esters are incorporated in chylomicrons which are transported by the lymph to the liver. Carotenoids are absorbed as such by the enterocytes and partially hydrolysed to retinol. In the liver retinol bound to binding proteins, is stored in fat-storing cells and parachym cells. Retinol and its metabolite retinoic acid, again bound to binding proteins, are excreted by the liver depending on the demands of the organism. After intake of large amounts of vitamin A it is presumed that the processes involved in the kinetics are saturable, and free retinol and retinoic acid can circulate in the body. The sensitivity of the different species to the teratogenic effect of vitamin A is very variable. This difference in sensitivity can be caused by the different routes of administration used, the kinetics of vitamin A as well as the specific sensitivity of the target organ, the embryo. From the literature can be concluded that the teratogenic effects are caused by retinol and retinoic acid. To develop a model for the kinetics and risk assessment of vitamin A in pregnant women some questions still remain after this literature study. What is the bioavailability of retinol after administration of retinol esters and carotenoids and is the absorption linear? Under which circumstances (vitamin A status) is the storage in the liver saturable? To what compound is the embryo exposed after intake of vitamin A and what are the differences in the kinetics of vitamin A after a high single dose intake and after chronically intake? These questions should be answered by investigations in our laboratory. The results of these studies shall contribute to the development of the model.<br>
Publisher:
Rijksinstituut voor Volksgezondheid en Milieu RIVM
Issue Date:
30-Sep-1992
Additional Links:
http://www.rivm.nl/bibliotheek/rapporten/642810001.html; http://www.rivm.nl/bibliotheek/rapporten/642810001.pdf
Type:
Onderzoeksrapport
Language:
nl
Sponsors:
HIGB
Appears in Collections:
RIVM official reports

Full metadata record

DC FieldValue Language
dc.contributor.authorOlling M-
dc.contributor.authorBode W-
dc.contributor.authorBruil M-
dc.contributor.authorGroen K-
dc.contributor.authorPiersma AH-
dc.date.accessioned2017-02-20T07:13:07-
dc.date.issued1992-09-30-
dc.identifier642810001-
dc.description.abstractThis report describes a literature study of the kinetics of vitamin A in different animal species. The goal of this study was to collect data to develop a model for risk assessment of the teratogenic effects of vitamin A. In the diet vitamin A is present as esters of retinol and as carotenoids. In the gastro-intestinal tract the retinylesters are hydrolysed and the retinol formed are absorbed by the enterocytes in the lumen of the intestine. In the enterocytes esterification of retinol takes place and these esters are incorporated in chylomicrons which are transported by the lymph to the liver. Carotenoids are absorbed as such by the enterocytes and partially hydrolysed to retinol. In the liver retinol bound to binding proteins, is stored in fat-storing cells and parachym cells. Retinol and its metabolite retinoic acid, again bound to binding proteins, are excreted by the liver depending on the demands of the organism. After intake of large amounts of vitamin A it is presumed that the processes involved in the kinetics are saturable, and free retinol and retinoic acid can circulate in the body. The sensitivity of the different species to the teratogenic effect of vitamin A is very variable. This difference in sensitivity can be caused by the different routes of administration used, the kinetics of vitamin A as well as the specific sensitivity of the target organ, the embryo. From the literature can be concluded that the teratogenic effects are caused by retinol and retinoic acid. To develop a model for the kinetics and risk assessment of vitamin A in pregnant women some questions still remain after this literature study. What is the bioavailability of retinol after administration of retinol esters and carotenoids and is the absorption linear? Under which circumstances (vitamin A status) is the storage in the liver saturable? To what compound is the embryo exposed after intake of vitamin A and what are the differences in the kinetics of vitamin A after a high single dose intake and after chronically intake? These questions should be answered by investigations in our laboratory. The results of these studies shall contribute to the development of the model.<br>en
dc.description.sponsorshipHIGB-
dc.formatapplication/pdf-
dc.format.extent43 p-
dc.format.extent1976 kb-
dc.language.isonl-
dc.publisherRijksinstituut voor Volksgezondheid en Milieu RIVM-
dc.relation.ispartofRIVM Rapport 642810001-
dc.relation.urlhttp://www.rivm.nl/bibliotheek/rapporten/642810001.html-
dc.relation.urlhttp://www.rivm.nl/bibliotheek/rapporten/642810001.pdf-
dc.subject07nl
dc.subjectvitamine anl
dc.subjectkinetieknl
dc.subjecttoxiciteitnl
dc.subjectteratogeniteitnl
dc.subject92-4nl
dc.subjectvitamin aen
dc.subjectkineticsen
dc.subjecttoxicityen
dc.subjectteratogenicityen
dc.titleKinetiek en teratogeniteit van vitamine A. Een literatuurstudienl
dc.title.alternativeKinetics and teratogenicity of vitamin A. A literature studyen
dc.typeOnderzoeksrapport-
dc.date.updated2017-02-20T06:13:07Z-
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