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Titolo:
EXPRESSION OF THE ORNITHINE DECARBOXYLASE GENE IN RESPONSE TO ASPARAGINE IN INTESTINAL EPITHELIAL-CELLS
Autore:
WANG JY; VIAR MJ; BLANNER PM; JOHNSON LR;
Indirizzi:
VET ADM MED CTR,DEPT SURG,10 N GREENE ST BALTIMORE MD 21201 UNIV MARYLAND,SCH MED,DEPT SURG BALTIMORE MD 21201 UNIV TENNESSEE,COLL MED,DEPT PHYSIOL & BIOPHYS MEMPHIS TN 38163
Titolo Testata:
American journal of physiology: Gastrointestinal and liver physiology
fascicolo: 1, volume: 34, anno: 1996,
pagine: 164 - 171
SICI:
0193-1857(1996)34:1<164:EOTODG>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAT SMALL-INTESTINE; MUCOSAL GROWTH; C-FOS; INDUCTION; POLYAMINES; MOUSE; MECHANISM; ACID; STIMULATION; ACTIVATION;
Keywords:
REFEEDING; GROWTH; INTESTINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
34
Recensione:
Indirizzi per estratti:
Citazione:
J.Y. Wang et al., "EXPRESSION OF THE ORNITHINE DECARBOXYLASE GENE IN RESPONSE TO ASPARAGINE IN INTESTINAL EPITHELIAL-CELLS", American journal of physiology: Gastrointestinal and liver physiology, 34(1), 1996, pp. 164-171

Abstract

Refeeding fasted rats significantly stimulates mucosal. growth and ornithine decarboxylase (ODC), the rate-limiting enzyme in the biosynthesis of polyamines, but the exact mechanism responsible for induction of ODC at the molecular level is unknown. Of normal dietary constituents, the amino acid asparagine markedly increases ODC activity and mucosal growth when administered intragastrically. The current study examined the expression of the ODC gene in IEC-6 cells (a line of normal ratsmall intestinal crypt cells) after exposure to asparagine. Cells were grown in Dulbecco's minimal essential medium containing 5% dialyzed fetal bovine serum. They were deprived of serum for 24 h before experiments. Exposure to asparagine at the dose of 10 mM resulted in the rapid increase in ODC mRNA levels. The increased expression of the ODC gene began 1 h after and peaked between 3 and 5 h after treatment with asparagine. Maximum increases in ODC mRNA levels were approximately fivefold the normal value. Increased levels of ODC mRNA in cells exposed to asparagine more paralleled by increases in ODC protein and enzyme activity and cellular polyamine levels. The half-life of mRNA for ODC in unstimulated IEC-6 cells was similar to 30 min and increased to >2 hin cells exposed to 10 mM asparagine. The half-life of ODC activity also was increased in asparagine-treated cells. When cellular protein synthesis was inhibited by cycloheximide, asparagine superinduced ODC mRNA levels. Furthermore, asparagine also significantly stimulated DNA synthesis in IEC-B cells. These results indicate that 1) asparagine stimulates ODC in IEC-6 cells through multiple pathways and 2) increasedODC mRNA levels result partly from a delay in the rate of degradation. These findings suggest that luminal amino acids stimulate gut mucosal growth in association with their ability to regulate ODC gene expression.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 21:03:08