On Fri, 17 Nov 1995, Suzanne Lewis wrote:
> What about lowering estrogen? Will that lengthen life also?
>> : :
> : : You say that melatonin has anti-gonadotropic function and that inhibiting
> : : the reproductive hormones is known to delay aging.. but removing the gonads
> : : do the same, no?
>> : Yes, Jean. Removing the gonads or delaying puberty has also
> : been shown to delay aging. REmoving the testicles is particularly
> : effective in that lowering testosterone levels has been shown to
> : extend life in both animals and humans. [[Cleveland Clinic Journal
> : of Medicine 1994; 61:276-84.]
> : However, a know a number of men who would prefer taking
> : melatonin ....
Suzanne - I don't know of specific studies that have examined the
relationship between estrogen and longevity, although it has been shown
that delaying puberty, which ostensibly would
entail reduced estrogen levels, does extend life. However, when
puberty is delayed, melatonin is likely to be elevated. {For a reference:
"A brief report:Melatonin-related hypogonadotropic hypogonadism" New
England Journal of Medicine 1992; 357:1356-59] Therefore, the ultimate
cause of the increased longevity could be a surplus of melatonin, not
an absence of estrogen.
As an aside, I ran across an interesting account in which
a group of men in a mental institution had their testicles removed in
the hopes that reduced testosterone levels would make them less violent.
(This took place in
Kansas in the 1950s). It is not known whether the men became more
tractable, but they did outlive the male patients who had been left intact,
most of the female patients, and also the scientists who had conceived the
diabolical experiment.
Now, what is curious about melatonin-induced longevity in animals -
it appears to *prevent* the age-related decline in testosterone levels. In
other words, the rodents have had a bounty of testosterone and also lived
considerably longer. THis was revealed in a recent study in Israel where
aging rats were kept on melatonin for a year. At the end of this period, 87%
of the melatonin-treated rats were still alive, compared with only 43% of
those not given the hormone. Yet the healthier, longer-lived, melatonin-
treated rats had three times as much testosterone.
[For a reference: NeuroReport 1995;6:785-88.]
There is much to puzzle about here.
Jo
Coauthor Melatonin: Your Body's Natural Wonder Drug (Bantam 1995)
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