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Expression of system N protein mRNA, but not system A or L, is upregulated by ileal epithelia of growing beef cattle in response to increased luminal supply of energy but not amino acids
Author(s) -
Liao Shengfa F,
Xue Yan,
Boling James A,
Matthews James C
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb416
Subject(s) - messenger rna , biology , amino acid , transporter , hydrolysate , in vivo , medicine , rumen , basal (medicine) , chemistry , endocrinology , biochemistry , gene , microbiology and biotechnology , hydrolysis , fermentation , insulin
To complete our in vivo study of how basal expression profiles of 20 amino acid ( AA ) transporter genes respond to increases in luminal supply of substrates or energy in the small intestine, total RNA was extracted from duodenal ( D ), jejunal ( J ), and ileal ( I ) epithelia of 18 ruminally and abomasally catheterized Angus steers (BW ? 260 kg) fed an alfalfa‐cube based diet at 1.3× NE m requirement and infused for 14 to 16 d with either (n = 6) water (basal) or corn starch hydrolysate (20% ME intake) into rumen (increased microbial AA) or abomasum (increased glucose/energy). The effect of infusion treatments on expression of mRNA encoding systems A (ATA1, 2, 3), N (SN1, 2), and L (LAT1, 2) neutral AA transporters was evaluated by real‐time RT‐PCR methodoloy. Basal expression of all mRNA but ATA3 differed ( P = 0.06) among D, J, and I: ATA1, D=J>I; ATA2, D=J, D=I, J>I; SN1, D>J=I; SN2, J>D=I; LAT1, D=J>I; LAT2, D=J, J=I, D 0.15) the mRNA content of these neutral AA transporters except that expression of SN1 and SN2 mRNA by I was increased ( P = 0.08) 57 and 51%, respectively, with increased luminal energy supply. This latter finding suggests that luminal energy supply may limit I expression of SN1 and SN2 mRNA. This study was funded by a USDA‐ARS Special Cooperative Agreement Grant.