Proliferation of mitochondria and gene expression of carnitine palmitoyltransferase and fatty acyl-CoA oxidase in rat skeletal muscle, heart and liver by hypolipidemic fatty acids
Gk. Totland et al., Proliferation of mitochondria and gene expression of carnitine palmitoyltransferase and fatty acyl-CoA oxidase in rat skeletal muscle, heart and liver by hypolipidemic fatty acids, BIO CELL, 92(5), 2000, pp. 317-329
Morphological and biochemical effects were induced at the subcellular level
in the skeletal muscle, heart and Liver of male rats as a result of feedin
g with EPA, DHA, and 3-thia fatty acids. The 3-thia fatty acid, tetradecylt
hioacetic acid (TTA) and EPA induced mitochondrial growth in type I muscle
fibers in both the diaphragm and soleus muscle, and the size distribution o
f mitochondrial areas followed a similar pattern. Only the 3-thia fatty aci
d induced mitochondrial growth in type II muscle fibers. The mean area occu
pied by the mitochondria and the size distribution of mitochondrial areas i
n both fiber types were highly similar in DHA-treated and control animals.
Only the 3-thia fatty acid increased the gene-expression of carnitine palmi
toyltransferase (CPT)-II in the diaphragm. In the heart, however, the gene
expression decreased. In hepatocytes an increase in the mean size of mitoch
ondria was observed after EPA treatment, concomitant with an increase in mi
tochondrial CPT-II gene expression. Administration of 2-methyl-substituted
EPA (methyl-EPA) induced a higher rate of growth of mitochondria than EPA.
At the peroxisomal level in the hepatocytes a 3-thia fatty acid, EPA, and D
HA increased the areal fraction concomitant with the induction of gene expr
ession of peroxisomal fatty acyl-CoA oxidase (FAO). In the diaphragm, mRNA
levels of FAO were not affected by EPA or DHA treatment, whereas gene expre
ssion was significantly increased after 3-thia fatty acid treatment. In the
heart, both 3-thia fatty acid, EPA and DHA tended to decrease the levels o
f FAO mRNA. The areal fraction of fat droplets in all three tissue types wa
s significantly lower in the groups treated with 3-thia fatty acid. In the
group treated with EPA a lower areal fraction of fat droplets was observed,
while the DHA group was similar to the control. This indicates that EPA an
d DHA have different effects on mitochondrial biogenesis. (C) 2000 Editions
scientifiques et medicales Elsevier SAS.