Hmmm. I guess I'd better make good on my threat.
So what's the story about melatonin and aging?
First, my credentials. Im a medical writer who has
spent the past three years researching melatonin in the process
of writing a book on the subject for the general public. My coauthor
is Russel J. Reiter, Ph.D., Professor of Neuroendocriniology at the U.of
Texas Health Science Center at San Antonio, widely regarded as an
international authority on melatonin. (Check him out on Medline or
in Scientific Citations.)
In addition to working with Reiter, I have interviewed over
fifty of the top melatonin researchers in the world and accumulated
my own reference library of over 1,000 papers on melatonin.
I suspect you all know what melatonin is -- a substance produced
by the pineal gland, primarily at night. It is commonly referred to
as a hormone because it has numerous hormonal properties, but it is also
an extremely potent antioxidant.
One of the first insights that melatonin might be related to
aging was the 1981 observation by Reiter that melatonin production
declined with age in rodents. [Melatonin is the most potent hormone known,
in that it has effects in the picogram range. This is also why it was
so late to come to researchers attention. Until the 1980s it was
impossible to measure with accuracy the amount of melatonin in the
bloodstream.] For a reference: Reiter, R. J. Experimental Aging
Research 1982; 8:27-30.
In 1985, the fact that melatonin had anti-gonadotropic functions (its
seasonal increase triggers seasonal reproduction in many animals, partly
due to melatonin-induced atrophy of the gonads) and that inhibiting
the reproductive hormones has been known to delay aging prompted a group
of Italian researchers to begin a rodent longevity experiment using
melatonin. [Maestroni, G.J., "Pineal Melatonin, Its Fundamental
Immunoregulatory ROle in Aging and Cancer." Annals of the NY Academy
of Sciences 1988; 521:140-148.] Giving mice a small amount of melatonin
in their nightly drinking water resulted in a 20% increase in longevity.
Numerous mice studies have been conducted since that time by
the same Italian researchers, with similar results. The only other
group to observe the anti-aging effects of melatonin on rodents has been
an Israeli group that published a study in 1995 showing that nightly
administration of melatonin in the drinking water of rats prevented
the age-related decline in immunity and allowed a much higher percentage
of the rats to reach old age. At 23 months of age -- and 15 months of
melatonin treatment -- 87% of the melatonin-treated rats were still
alive compared to 43% of those not given the hormone. Most of
the survivingg control rats had pneumonia, which was not observed in the
melatonin group. ["Effects of Long-term administration of melatonin ..
on the ageing Rat" NeuroReport 1995; 6:785-88.]
Longevity studies involving melatonin have not been conducted
using other animals.
If melatonin does indeed have anti-aging properties, what
might be the explanation?
Reiter believes it is due to its unparalleled antioxidant
properties, which I will explore in a subsequent post.
Jo
For a Melatonin FAQ go to http://www.teleport.com/~jor
+-----------------------------------+-----------------------------------------+
| Jo Robinson | jor at teleport.com |
| (503)284-4676 | 2826 NE 18th Portland, OR 97212 |
+-----------------------------------+------------------------------------y-----+
