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Effects of bile diversion in rats on intestinal sphingomyelinases and ceramidase.

Duan, Rui-Dong LU ; Verkade, H J; Cheng, Yajun LU ; Havinga, R and Nilsson, Åke LU (2007) In Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids 1771(2). p.196-201
Abstract
Alkaline sphingomyelinase (Alk-SMase) and neutral ceramidase (N-CDase) in the intestinal microvillar membrane are responsible for dietary sphingomyelin digestion. The activities of the enzymes require the presence of bile salt, and the enzymes can be released into the gut lumen in active forms by bile salts and trypsin. It is unclear to what extent that the intestinal presence of bile salts is critical for the intraluminal activity of these enzymes. We compared the activities of Alk-SMase, N-CDase, and other types of SMases in control and permanently bile diverted rats. In the intestinal tract of control rats, the activity of Alk-SMase was profoundly higher than those of acid and neutral Wases. Bile diversion reduced Alk-SMase activity by... (More)
Alkaline sphingomyelinase (Alk-SMase) and neutral ceramidase (N-CDase) in the intestinal microvillar membrane are responsible for dietary sphingomyelin digestion. The activities of the enzymes require the presence of bile salt, and the enzymes can be released into the gut lumen in active forms by bile salts and trypsin. It is unclear to what extent that the intestinal presence of bile salts is critical for the intraluminal activity of these enzymes. We compared the activities of Alk-SMase, N-CDase, and other types of SMases in control and permanently bile diverted rats. In the intestinal tract of control rats, the activity of Alk-SMase was profoundly higher than those of acid and neutral Wases. Bile diversion reduced Alk-SMase activity by 85% in the small intestinal content, and by 68% in the faeces, but did not significantly change the activity in the intestinal mucosa. Western blot showed a marked reduction of the enzyme in the intestinal lumen but not mucosa. N-CDase activities both in the intestinal mucosa and content were reduced by bile diversion. Bile diversion also decreased aminopeptidase N activity in the content and increased that in the mucosa, but had no effects on that of alkaline phosphatase. In conclusion, the presence of bile salts is important for maintaining high intraluminal levels of Alk-SMase and N-CDase, two key enzymes for hydrolysis of sphingomyelin in the gut. We speculate that the sphingomyelin hydrolysis in cholestatic conditions is impaired not only by reduced hydrolytic activity but also by deficient dissociation of the enzymes from the membrane. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
volume
1771
issue
2
pages
196 - 201
publisher
Elsevier
external identifiers
  • wos:000244639100008
  • scopus:33846837412
ISSN
1388-1981
DOI
10.1016/j.bbalip.2006.12.001
language
English
LU publication?
yes
id
2fea1906-449d-4cca-ac43-8bace27c1bba (old id 165122)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=17204455&dopt=Abstract
date added to LUP
2007-06-27 16:24:53
date last changed
2017-01-01 07:20:57
@article{2fea1906-449d-4cca-ac43-8bace27c1bba,
  abstract     = {Alkaline sphingomyelinase (Alk-SMase) and neutral ceramidase (N-CDase) in the intestinal microvillar membrane are responsible for dietary sphingomyelin digestion. The activities of the enzymes require the presence of bile salt, and the enzymes can be released into the gut lumen in active forms by bile salts and trypsin. It is unclear to what extent that the intestinal presence of bile salts is critical for the intraluminal activity of these enzymes. We compared the activities of Alk-SMase, N-CDase, and other types of SMases in control and permanently bile diverted rats. In the intestinal tract of control rats, the activity of Alk-SMase was profoundly higher than those of acid and neutral Wases. Bile diversion reduced Alk-SMase activity by 85% in the small intestinal content, and by 68% in the faeces, but did not significantly change the activity in the intestinal mucosa. Western blot showed a marked reduction of the enzyme in the intestinal lumen but not mucosa. N-CDase activities both in the intestinal mucosa and content were reduced by bile diversion. Bile diversion also decreased aminopeptidase N activity in the content and increased that in the mucosa, but had no effects on that of alkaline phosphatase. In conclusion, the presence of bile salts is important for maintaining high intraluminal levels of Alk-SMase and N-CDase, two key enzymes for hydrolysis of sphingomyelin in the gut. We speculate that the sphingomyelin hydrolysis in cholestatic conditions is impaired not only by reduced hydrolytic activity but also by deficient dissociation of the enzymes from the membrane.},
  author       = {Duan, Rui-Dong and Verkade, H J and Cheng, Yajun and Havinga, R and Nilsson, Åke},
  issn         = {1388-1981},
  language     = {eng},
  number       = {2},
  pages        = {196--201},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids},
  title        = {Effects of bile diversion in rats on intestinal sphingomyelinases and ceramidase.},
  url          = {http://dx.doi.org/10.1016/j.bbalip.2006.12.001},
  volume       = {1771},
  year         = {2007},
}