Neurosci Lett. 2006 Apr 18; [Epub ahead of print
Treatment with dehydroepiandrosterone (DHEA) stimulates oxidative energy
metabolism in the cerebral mitochondria A comparative study of effects in
old and young adult rats.
Patel MA, Katyare SS.
Department of Biochemistry, Faculty of Science, The Maharaja Sayajirao
University of Baroda, Vadodara, Gujarat 390 002, India.
The content of the neurosteroids, dehydroepiandrosterone (DHEA) in the
brain decreases with aging. Also the oxidative energy metabolism is known
to decrease with aging. Hence we examined the effects of treatment with
DHEA (0.2 or 1.0mg/kg body weight for 7 days) on oxidative energy
metabolism in brain mitochondria from old and young adult rats. State 3
respiration rates in brain mitochondria from old animals were considerably
lower than those in young adults. Treatment with DHEA stimulated state 3
and state 4 respiration rates in both the groups of the animals in a
dose-dependent manner. In the old rats following DHEA treatment, the state
3 respiration rates became comparable to or increased beyond those of
untreated young adults. In contrast to the old rats, stimulatory effect of
DHEA treatment was of greater magnitude in the young adults. However, at
higher dose (1.0mg) the effect declined. Cytochrome aa(3) content in the
brain mitochondria from old rats was significantly low but the content of
cytochrome b was unchanged while the content of cytochromes c+c(1) had
increased. Treatment with DHEA increased the content of cytochrome aa(3)
and b in old as well as in young adult animals. Higher dose of DHEA (1.0mg)
had adverse effect on the content of cytochrome c+c(1). DHEA treatment
stimulated ATPase activity in a dose-dependent manner in young adult rats
whereas in the old rats the effect on ATPase activity was marginal.
Dehydrogenases activities were somewhat lower in the old rats. DHEA
treatment stimulated mitochondrial dehydrogenases activities in both the
groups. Results of our studies suggest that judicious use of DHEA treatment
can improve oxidative energy metabolism parameters in brain mitochondria
from young adult as well as old rats.