Document Detail


Sodium-dependent phosphate uptake in the jejunum is post-transcriptionally regulated in pigs fed a low-phosphorus diet and is independent of dietary calcium concentration.
MedLine Citation:
PMID:  20164365     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In rodents, severe dietary P restriction increases active phosphate absorption by the intestine. However, it remains unknown if moderate dietary P restriction has a similar effect. Weanling pigs (n = 32; body weight 7.4 +/- 0.55 kg) were used in a 2 x 2 factorial design and fed dietary available P (aP) concentrations of 0.23 or 0.40% and Ca concentrations of 0.58 or 1.00% for 14 d. Diets were formulated on an aP basis instead of a total P basis, because pigs are unable to absorb phytate-P present in corn and soybean meal. Jejunal segments were mounted in modified Ussing chambers for determination of Na(+)-dependent nutrient transport. Intestinal mucosal scrapings were taken for RNA isolation and brush border membrane (BBM) vesicle isolation. Na(+)-dependent phosphate uptake and gene expression of Na-phosphate cotransporter IIb (NaPi-IIb), SGLT-1 (sodium/glucose cotransporter-1), and calbindin D(9k) and protein expression of NaPi-IIb were evaluated. Na(+)-dependent phosphate transport increased (P < 0.05) 46% as dietary aP concentration was decreased. However, increased Na(+)-dependent phosphate uptake was not accompanied by increased NaPi-IIb mRNA expression. Expression of NaPi-IIb protein in the BBM increased (P < 0.01) 84% in pigs fed low-P diets compared with pigs fed adequate-P diets. No dietary Ca effects or aP x Ca interactions were detected for Na-dependent P uptake, mRNA or protein expression of NaPi-IIb, or mRNA expression of calbindin D(9k). These data suggest that restricting dietary aP concentration by only 43% stimulates Na(+)-dependent phosphate uptake and expression of the NaPi-IIb protein in the BBM of the small intestine and through a post-transcriptional mechanism.
Authors:
Kari L Saddoris; James C Fleet; John S Radcliffe
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial     Date:  2010-02-17
Journal Detail:
Title:  The Journal of nutrition     Volume:  140     ISSN:  1541-6100     ISO Abbreviation:  J. Nutr.     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-03-22     Completed Date:  2010-04-30     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  0404243     Medline TA:  J Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  731-6     Citation Subset:  IM    
Affiliation:
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
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MeSH Terms
Descriptor/Qualifier:
Animal Feed / analysis
Animal Nutritional Physiological Phenomena
Animals
Calcium / metabolism*
Calcium, Dietary / administration & dosage
Diet / veterinary*
Female
Jejunum / metabolism*
Male
Phosphates / pharmacokinetics*
Phosphorus, Dietary / administration & dosage
RNA Processing, Post-Transcriptional*
Sodium / metabolism*
Sodium-Phosphate Cotransporter Proteins, Type IIb / genetics,  metabolism
Swine
Grant Support
ID/Acronym/Agency:
R01 DK054111-12/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Calcium, Dietary; 0/Phosphates; 0/Phosphorus, Dietary; 0/Sodium-Phosphate Cotransporter Proteins, Type IIb; 7440-23-5/Sodium; 7440-70-2/Calcium
Comments/Corrections

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