From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Fri Apr 04 2003 - 15:47:39 MST
On Fri, 4 Apr 2003, Ramez Naam wrote (among some other things):
> My first reaction is a bit skeptical. Creatures with increased SOD
> production don't act like CR creatures. CR creatures are smaller and
> have lower fertility.
[many snips]
I would strongly suggest *not* going there (in attempting to make sense
of this at this time).
Yes the mitochondria produce free radicals -- this appears to be related
to the "throughput" of the mitochondrial respiratory chain [when it gets
backed up more free radicals get generated] -- but one of the life-extending
mutations in C. elegans involves insufficient Co-Q9 or Co-Q10 (so the
mitochondrial transport chains get backed up, do suffer reduced transport
capacity and perhaps greater free radical generation. But this may be
offset by the reduced ATP generation (effectively CR). But then in mammals
you have the uncoupling proteins (which serve to facilitate heat production and
would reduce the backup in the mitochondrial transport chains) (I posted
extensively about this probably about a year ago). But they might generate more free
radicals if the free radical production is an inherent part of the respiratory
glucose/oxygen consumption process. (I.e. more heat == more free radicals).
But then the free radicals could be offset by anti-oxidants such as
estrogen or alpha-lipoic acid that may not be present in large quantities
in more primitive organisms.
If one wades into this one is wading into one of the most complex
intellectual problems I'm aware of -- and given the state of our
knowledge base I personally don't think resolving it isn't going
to be pretty.
Go relax on the beach -- let the grad students that actually
need to debate these things deal with it.
R.
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