Vol. 283, Issue 5, H1750-H1760, November 2002
Aging-induced decrease in the PPAR-
level in hearts is
improved by exercise training
Motoyuki
Iemitsu1,
Takashi
Miyauchi1,
Seiji
Maeda1,
Takumi
Tanabe2,
Masakatsu
Takanashi1,
Yoko
Irukayama-Tomobe1,
Satoshi
Sakai1,
Hajime
Ohmori2,
Mitsuo
Matsuda2, and
Iwao
Yamaguchi1
1 Cardiovascular Division, Department of Internal
Medicine, Institute of Clinical Medicine, 2 Institute of
Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki
305-0006, Japan
Peroxisome proliferator-activated
receptor (PPAR)-
, a transcriptional activator, regulates genes of
fatty acid (FA) metabolic enzymes. To study the contribution of
PPAR- to exercise training-induced improvement of FA metabolic
capacity in the aged heart, we investigated whether PPAR- signaling
and expression of its target genes in the aged heart are affected by
exercise training. We used hearts of sedentary young rat (4 mo old),
sedentary aged rat (23 mo old), and swim-trained aged rat (23 mo old,
training for 8 wk). The mRNA and protein expression of PPAR- in the
heart was significantly lower in the sedentary aged rats compared with
the sedentary young rats and was significantly higher in the
swim-trained aged rats compared with the sedentary aged rats. The
activity of PPAR- DNA binding to the transcriptional regulating
region on the FA metabolic enzyme genes, the mRNA expression of
3-hydroxyacyl CoA dehydrogenase (HAD) and carnitine palmitoyl
transferase-I, which are PPAR- target genes, and the enzyme activity
of HAD in the heart altered in association with changes of the
myocardial PPAR- mRNA and protein levels. These findings suggest
that exercise training improves aging-induced downregulation in
myocardial PPAR--mediated molecular system, thereby contributing to
the improvement of the FA metabolic enzyme activity in the trained-aged hearts.
peroxisome proliferator-activated receptor-; swimming training; aged rat; fatty acid
