MELATONIN EXTENDS LIFESPAN: NEW STUDY
Israeli scientists have just reported the results of a new
lifespan study with melatonin in aging rats (NeuroReport,
6, 785-788, 1995). This study reinforces earlier lifespan
studies with several strains of mice (see "Evidence That
Melatonin Is An Anti-Aging Therapy").
The scientists used male CD rats, 11-13 months old in
their study. These rats have a maximum lifespan of 30-35
months, with 20% mortality at 20-25 months.
In addition to the effect of melatonin (in the drinking
water) on the lifespan of these rats, they also sought to
determine if melatonin could counteract the decrease in
melatonin binding sites in the rat brain.
Results Of Study
The study was conducted for 15-16 months, after which
the animals were sacrificed and their brains tested. The
scientists found that supplemental melatonin:
"...markedly increased the number of rats which survived
to the age of 26-29 months... 43% of the control group of
16 animals survived to the age of 27-29 months... which is
in agreement with the life expectancy of this species. Of
the melatonin-treated group of 15 animals 87% survived
to the age of 27-29 months. In the control group, 5 of the
7 survivors suffered from severe pneumonia whereas the
melatonin-treated animals either did not suffer from
pneumonia, or had very weak symptoms."
The scientists also found that there was a 54%-to-115%
increase in melatonin binding sites in the brains of the
melatonin-treated animals depending upon which binding
site they looked at, and that the treated animals had higher
circulating testosterone levels than the controls. This
rejuvenation effect may have been one of the reasons for
the extended lifespan of the melatonin-treated rats.