Growth factors regulation of rabbit sodium-dependent neutral amino acid transporter ATB0 and oligopeptide transporter 1 mRNAs expression after enteretomy.
BACKGROUND
Sucessful intestinal adaptation after massive enterectomy is dependent on increased efficiency of nutrient transport. However, midgut resection (MGR) in rabbits induces an initial decrease in sodium-dependent brush border neutral amino acid transport, whereas parenteral epidermal growth factor (EGF) and growth hormone (GH) reverse this downregulation. We investigated intestinal amino acid transporter B0 (ATB0) and oligopeptide transporter 1 (PEPT 1) mRNA expression after resection and in response to EGF and/or GH.


METHODS
Rabbits underwent anesthesia alone (control) or proximal, midgut, and distal resections. Full-thickness intestine was harvested from all groups on postoperative day (POD) 7, and on POD 14 from control and MGR rabbits. A second group of MGR rabbits received EGF and/or GH for 7 days, beginning 7 days after resection. ATB0 and PEPT 1 mRNA levels were determined by Northern blot analysis.


RESULTS
In control animals, ileal ATB0 mRNA abundance was three times higher than jejunal mRNA, whereas PEPT 1 mRNA expression was similar. By 7 and 14 days after MGR, jejunal ATB0 mRNA abundance was decreased by 50% vs control jejunum. A 50% decrease in jejunal PEPT 1 message was delayed until 14 days after MGR. Treatment with EGF plus GH did not alter ATB0 mRNA expression but doubled PEPT 1 mRNA in the jejunum.


CONCLUSIONS
The site of resection, time postresection, and growth factors treatment differentially influence ATB0 and PEPT 1 mRNA expression. Enhanced sodium-dependent brush border neutral amino acid transport with GH plus EGF administration is independent of increased ATB0 mRNA expression in rabbit small intestine after enterectomy.
Avissar
N E
NE
Department of Surgery, University of Rochester Medical Center, New York 14642-8410, USA. nelly_avissar@urmc.rochester.edu
Ziegler
T R
TR
Wang
H T
HT
Gu
L H
LH
Miller
J H
JH
Iannoli
P
P
Leibach
F H
FH
Ganapathy
V
V
Sax
H C
HC
D000222:Adaptation, Physiological / Q000502:physiology*; D026962:Amino Acid Transport System ASC; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology* / Q000502:physiology; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000494:pharmacology* / Q000502:physiology; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism / Q000601:surgery*; D008297:Male; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D000074011:Peptide Transporter 1; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D011897:Random Allocation; D011991:Receptors, Virus / Q000235:genetics / Q000378:metabolism*; D027981:Symporters
D026962:Amino Acid Transport System ASC; D000596:Amino Acids; D002352:Carrier Proteins; D000074011:Peptide Transporter 1; D012333:RNA, Messenger; D011991:Receptors, Virus; C082186:SLC15A1 protein, human; D027981:Symporters; D004815:Epidermal Growth Factor; D013006:Growth Hormone