Open AccessPeripheral Nerve Sphingomyelin and Cerebroside are Both Formed Via two Metabolically and Kinetically Distinct Pathways In vivo
Author(s) -
Heape Anthony M.,
Boiron Françoise,
Bessoule JeanJacques,
Cassagne Claude
Publication year - 1994
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1994.tb20074.x
Subject(s) - sphingomyelin , ceramide , sphingolipid , cerebroside , in vivo , acylation , biochemistry , chemistry , substrate (aquarium) , sphingosine , lipid signaling , enzyme , stereochemistry , biology , cholesterol , receptor , apoptosis , ecology , microbiology and biotechnology , catalysis
We have studied the labeling kinetics of peripheral nerve sphingolipids in vivo. The kinetic analysis of the labeling profiles observed for the various sphingolipids demonstrated that 90% of cerebrosides, but only 30% of sphingomyelin, were synthesized via a de novo synthesized ceramide intermediate following the injection of 1–4 pmol [ 3 H]palmitate into mouse sciatic nerves. The remaining sphingolipid labeling (30% of the total) was due to direct acylation events, using free fatty acids originating from a pool different from those implicated in the de novo ceramide pathway. Direct acylation events ceased within 1 h following substrate administration, while labeling via the ceramide pathway continued through 5 h. The results provide the first in vivo demonstration that the formation of cerebrosides and sphingomyelin in peripheral nerves in situ can be simultaneously assured via two metabolically and kinetically distinct pathways that employ different fatty acid pools.