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The effect of nutrients on the rate of protein degradation in isolated small intestinal enterocytes from Sprague-Dawley rats Taghadomy Saberi, Mohsen
Abstract
Nutrients affect small intestinal protein mass and metabolism. Studies on the effect of nutrients on small intestinal protein degradation are limited due to a lack of a proper method. The objectives of this study were to establish a method to directly estimate protein degradation in isolated enterocytes from rats, and to test the effect of energy substrates and amino acids on protein degradation. Male Sprague-Dawley rats (150-200 g, n ≥8 per treatment) were used. Cell viability, tyrosine release as an indicator of protein degradation, and the effect of osmolarity were measured to establish the method. The effects of energy substrates (50 mM glucose, 20 mM (β-hydroxybutyrate, 4.7 mM butyrate, and 30 mM glutamine) and amino acid solutions (30 mM amino acids mix, 30 mM glutamate, 1% ammonium, and 30 mM amino acids mix plus 50 mM glucose) on protein degradation were measured. Average viability at time 30 min was 85.8% (range 81-94%). Tyrosine release was linear over the course of experiments, indicating constant protein degradation (R²= 0.9943) (p<0.05). Osmolarity, glucose, and glutamine had no effect on protein degradation. [β-hydroxybutyrate significantly decreased it (-16%; p<0.05), whereas butyrate slightly increased it (+ 5%; p<0.05). The mixture of amino acids and glutamate increased (p<0.05) protein degradation (+ 10%) compared to control. Ammonium had no effect. The mixture of amino acids plus glucose decreased (-13%; p<0.05) protein degradation compared to the mix of amino acids only. High viability and constant rate of protein degradation indicate successful establishment of a method to estimate protein degradation in isolated small intestinal enterocytes from rats. The mixture of amino acids or glutamate may have acted as an energy source for the highly energy dependent enterocyte. Addition of glucose to the mixture of amino acids may have decreased the concentration of amino acids in tissue and abolished their effect. The large effect of β-hydroxybutyrate suggests a potential positive role for ketone bodies to limit the loss of small intestinal protein mass by decreasing protein degradation. These findings might be particularly important in catabolic conditions such as starvation or total parenteral nutrition, where the loss of small intestinal protein mass is substantial.
Item Metadata
Title |
The effect of nutrients on the rate of protein degradation in isolated small intestinal enterocytes from Sprague-Dawley rats
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2007
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Description |
Nutrients affect small intestinal protein mass and metabolism. Studies on the effect of nutrients
on small intestinal protein degradation are limited due to a lack of a proper method. The
objectives of this study were to establish a method to directly estimate protein degradation in
isolated enterocytes from rats, and to test the effect of energy substrates and amino acids on
protein degradation. Male Sprague-Dawley rats (150-200 g, n ≥8 per treatment) were used. Cell
viability, tyrosine release as an indicator of protein degradation, and the effect of osmolarity
were measured to establish the method. The effects of energy substrates (50 mM glucose, 20
mM (β-hydroxybutyrate, 4.7 mM butyrate, and 30 mM glutamine) and amino acid solutions (30
mM amino acids mix, 30 mM glutamate, 1% ammonium, and 30 mM amino acids mix plus 50
mM glucose) on protein degradation were measured. Average viability at time 30 min was
85.8% (range 81-94%). Tyrosine release was linear over the course of experiments, indicating
constant protein degradation (R²= 0.9943) (p<0.05). Osmolarity, glucose, and glutamine had no
effect on protein degradation. [β-hydroxybutyrate significantly decreased it (-16%; p<0.05),
whereas butyrate slightly increased it (+ 5%; p<0.05). The mixture of amino acids and glutamate
increased (p<0.05) protein degradation (+ 10%) compared to control. Ammonium had no effect.
The mixture of amino acids plus glucose decreased (-13%; p<0.05) protein degradation
compared to the mix of amino acids only. High viability and constant rate of protein degradation
indicate successful establishment of a method to estimate protein degradation in isolated small
intestinal enterocytes from rats. The mixture of amino acids or glutamate may have acted as an
energy source for the highly energy dependent enterocyte. Addition of glucose to the mixture of
amino acids may have decreased the concentration of amino acids in tissue and abolished their effect. The large effect of β-hydroxybutyrate suggests a potential positive role for ketone bodies
to limit the loss of small intestinal protein mass by decreasing protein degradation. These
findings might be particularly important in catabolic conditions such as starvation or total
parenteral nutrition, where the loss of small intestinal protein mass is substantial.
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Genre | |
Type | |
Language |
eng
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Date Available |
2011-03-22
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0101268
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.