Marginally excessive iron loading transiently blocks mucosal iron uptake in iron-deficient rats.
Am J Physiol Gastrointest Liver Physiol
; 307(1): G89-97, 2014 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-24833704
ABSTRACT
Regular "mucosal block" is characterized by decreased uptake of a normal iron load 3-72 h after the administration of excess iron (generally 10 mg) to iron-deficient animals. We found that short-acting mucosal block could be induced by much lower iron concentration and much shorter induction time than previously reported, without affecting levels of gene expression. A rapid endocytic mechanism was reported to decrease intestinal iron absorption after a high iron load, but the activating iron load and the time to decreased absorption were undetermined. We assessed the effects of 30-2,000 µg iron load on iron uptake in the duodenal loop of iron-deficient and iron-sufficient rats under anesthesia. One hour later, mucosal cellular iron uptake in iron-deficient rats administered 30 µg iron was 76.1%, decreasing 25% to 50.7% in rats administered 2,000 µg iron. In contrast, iron uptake by iron-sufficient rats was 63% (range 60.3-65.5%) regardless of iron load. Duodenal mucosal iron concentration was significantly lower in iron-deficient than in iron-sufficient rats. Iron levels in portal blood were consistently higher in iron-deficient rats regardless of iron load, in contrast to the decreased iron uptake on the luminal side. Iron loading blocked mucosal uptake of marginally excess iron (1,000 µg), with a greater effect at 15 min than at 30 min. The rapid induction of short-acting mucosal block only in iron-deficient rats suggests DMT1 internalization.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Distúrbios do Metabolismo do Ferro
/
Duodeno
/
Deficiências de Ferro
/
Absorção Intestinal
/
Mucosa Intestinal
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol Gastrointest Liver Physiol
Assunto da revista:
FISIOLOGIA
/
GASTROENTEROLOGIA
Ano de publicação:
2014
Tipo de documento:
Article