Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 52, Issue 5 B255-B259, Copyright © 1997 by The Gerontological Society of America
Exercise training reverses the age-related decline in tyrosine hydroxylase expression in rat hypothalamus
N Tumer, JS LaRochelle and M Yurekli
Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center, Gainesville, Florida, USA.
Tyrosine hydroxylase (TH) is the rate-limiting enzymatic step in the
catecholamine biosynthesis pathway. Some studies have demonstrated that
aging is associated with a decrease in TH activity and TH mRNA in rat
hypothalamus. We previously demonstrated that exercise training can
decrease TH gene expression in the adrenal medulla of young but not
senescent rats. This study was designed to examine the effects of endurance
training on the TH expression in hypothalamus with aging. To this end, we
assessed TH mRNA, TH immunoreactivity, and TH activity with or without
exercise training. Young and old F-344 female rats were trained by
treadmill running for 8 weeks. All parameters examined were significantly
lower in hypothalamus of old (25-month) compared with young (5-month)
control animals (p < .05). Exercise training significantly elevated TH
mRNA (n = 5-7 in each group), TH immunoreactivity (n = 5-8 in each group),
and TH activity (n = 12-13 young groups and n = 6 old groups) in the
hypothalamus of old animals (p < .05), but there was no significant
change in any of these parameters in young animals following training.
These data indicate that endurance training can reverse the age-related
decline in catecholamine biosynthesis in the hypothalamus.
