Lactase phlorizin hydrolase synthesis is decreased in protein-malnourished pigs.

Abstract

We have examined the effect of protein malnutrition on brush border (BB) lactase phlorizin hydrolase (LPH) synthesis in young pigs. Two groups of four 3-wk-old pigs were fed diets containing either 19 g soy protein, 63 g carbohydrate and 5 g fat per 100 g diet (a protein-sufficient diet) or 3 g soy protein, 85 g carbohydrate and 5 g fat per 100 g diet (a protein-deficient diet). After 8 wk of consuming the diets, pigs were infused intravenously with 2H3-leucine for 8 h, then killed. The jejunum was collected for measurement of lactase activity, LPH mRNA abundance and the rate of LPH post-translational synthesis. Lactase activities did not differ between groups (mean 8.1 +/- 1.2 micromol x min(-1) x g mucosa(-1)). LPH mRNA abundance relative to elongation factor-1alpha mRNA (the constitutive/reference mRNA) was significantly (P < 0.05) higher in well-nourished pigs (0.36 +/- 0.03%) than in protein-malnourished pigs (0.21 +/- 0.02%). The rate constants of BB LPH post-translational synthesis were also significantly higher in the well-nourished (103 +/- 9% x d(-1)) than in the protein-malnourished pigs (66 +/- 8% x d(-1)). Further, the absolute synthesis rate of BB LPH, a measure of the amount of enzyme synthesized per gram of tissue, was significantly higher in well-nourished than in protein-malnourished pigs (in arbitrary units, 892 +/- 90 vs. 450 +/- 34, respectively). Thus, protein malnutrition affects both LPH mRNA abundance and post-translational processing in young pigs.

• Authors: M A Dudley, L Wykes, A W Dudley Jr, M Fiorotto, D G Burrin, J Rosenberger, F Jahoor, P J Reeds
• Journal: The Journal of nutrition (J Nutr) Vol. 127 Issue 5 Pg. 687-93 (May 1997) ISSN: 0022-3166 [Print] United States
• PMID: 9164987 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• RNA, Messenger
• Serum Albumin
• Lactase-Phlorizin Hydrolase

Topics

• Animals
• Animals, Newborn
• Blotting, Northern (methods)
• Diet, Protein-Restricted
• Jejunum (chemistry, cytology, enzymology)
• Lactase-Phlorizin Hydrolase (biosynthesis, genetics)
• Microvilli (chemistry, enzymology)
• Protein Biosynthesis (physiology)
• Protein Processing, Post-Translational
• Protein-Energy Malnutrition (enzymology)
• RNA, Messenger (analysis, metabolism)
• Serum Albumin (metabolism)
• Swine