Vol. 93, Issue 2, 463-468, August 2002
Effect of exercise on mRNA expression of select adrenal
medullary catecholamine biosynthetic enzymes
S. Remzi
Erdem2,
Haydar A.
Demirel3,
Christopher S.
Broxson1,
Bistra B.
Nankova4,
Esther L.
Sabban4, and
Nihal
Tümer1,2
1 Geriatric Research, Education and Clinical Center,
Malcom Randall Veterans Affairs Medical Center,
2 Department of Pharmacology and Therapeutics,
University of Florida College of Medicine, and 3 Center
for Exercise Science, University of Florida, Gainesville, Florida
32610; and 4 Department of Biochemistry and
Molecular Biology, New York Medical College, Valhalla, New York 10595
The effect of submaximal
endurance training (SET) on sympathoadrenal activity is not clear.
We tested the hypothesis that SET (90 min/day, 5 days/wk, for 12 wk)
elevates mRNA expression of catecholamine (CA) biosynthetic enzymes,
tyrosine hydroxylase (TH) and dopamine-
-hydroxylase (DH) in the
adrenal medullae of adult, female Sprague-Dawley rats. SET increased TH
protein level by 35%, TH activity by 62%, TH mRNA expression by 40%,
and DH mRNA expression by 67%. In addition, we examined the effect of SET on Fos-related antigens (FRAs), FRA-2 immunoreactivity, and
activator protein (AP)-1 binding activity. SET increased AP-1 binding
activity by 78%; however, it did not affect late FRAs and FRA-2
immunoreactivity. Because the regulation of neuropeptide Y (NPY) often
parallels that of CAs, we also examined the effect of SET on NPY mRNA
expression. Indeed, SET elevated NPY mRNA expression as well. We
conclude that 1) SET elicits a pretranslational stimulatory effect on adrenomedullary CA biosynthetic enzymes, 2)
another immediate early mRNA product, rather than FRA-2, may contribute to the increase in AP-1 binding activity in response to SET, and 3) SET increases NPY mRNA expression.
chronic physical training; tyrosine hydroxylase; activator
protein-1; Fos-related antigen-2; neuropeptide Y; dopamine--hydroxylase
