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Inhibition of serine palmitoyltransferase by myriocin, a natural mycotoxin, causes induction of c-myc in mouse liver.

Authors
He-Q; Johnson-VJ; Osuchowski-MF; Sharma-RP
Source
Mycopathologia 2004 Apr; 157(3):339-347
NIOSHTIC No.
20025273
Abstract
Myriocin, a fungal metabolite isolated from Myriococcum albomyces, Isaria sinclairi, and Mycelia sterilia, is a potent inhibitor of serine palmitoyltransferase (SPT), a key enzyme in de novo synthesis of sphingolipids. To evaluate the biological effects of myriocin in vivo, we investigated the levels of free sphingoid bases and expression of selected genes regulating cell growth in mouse liver. Male Balb/c mice, weighing 22 g were injected intraperitoneally with myriocin at 0, 0.1, 0.3, and 1.0 mg kg-1 body weight daily for 5 days. Animals were euthanized 24 hours after the last treatment. Levels of plasma alanine aminotransferase and aspartate aminotransferase were not significantly altered by the treatment. A dose-dependent decrease in free sphinganine but not sphingosine was detected by high performance liquid chromatography in both liver and kidney. The decrease of free sphinganine paralleled the decrease in SPT activity. Reverse transcriptase polymerase chain reaction analysis on liver mRNA revealed an increase in expression of c- myc, but no changes in tumor necrosis factor a, transforming growth factor , and hepatocyte growth factor. Results showed that myriocin blocked de novo synthesis of sphingolipids in vivo by SPT inhibition and induced c- myc expression in liver.
Keywords
Fungi; Fungicides; Metabolites; Metabolism; In-vivo-study; Laboratory-animals; Liver; Liver-cells; Microorganisms
CODEN
MYCPAH
Publication Date
20040401
Document Type
Journal Article
Fiscal Year
2004
NTIS Accession No.
NTIS Price
Issue of Publication
3
ISSN
0301-486X
NIOSH Division
HELD
Source Name
Mycopathologia
State
WV
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