From: Joao Pedro de Magalhaes (joao.magalhaes@fundp.ac.be)
Date: Thu Apr 12 2001 - 08:37:54 MDT
Hi!
You wrote:
>Thanks for pointing this out to me. I'll need to read more about
>sexual maturation in mice before I can form an opinion. If you happen
>to have any references, or even partly-remembered names of authors or
>paper titles, I'd be grateful. Either way, when I find out more about
>this, I'll follow up.
I took "CR mice taking twice the time to reach sexual maturity" from
Hayflick's book. Finch's book also offers some thoughts and, as usual, a
very complete set of findings.
>> As you probably know, if you increase the caloric intake of mice, they live
>> the same. So, total energy consumption does not explain everything. You can
>
>I'm not sure I understand. Do you mean if you feed mice a higher calorie
>diet than they would ordinarily eat? Or do you mean if you take CR mice
>and put them on a normal diet, thus making them no longer CR?
Neither. This was an experiment done in the 80s to disprove Kleiber's rule
(which claimed that maximum lifespan correlates with cellular metabolic
rates). What they did was place mice under lower temperatures. Since they
had to burn more energy to compensate for the lower temperature, they ate
44% more. Yet they lived the same as the controls. Ref:
Holloszy, J. O., and Smith, E. K. (1986). "Longevity of cold-exposed rats: a
reevaluation of the "rate-of-living theory"." J Appl Physiol 61(5):1656-60.
There's another guy trying to repeat this experiment but I forgot his name
-- I know he works in Scotland.
>"Atrophies" implies pathological processes, and this is not the case
>in CR animals. They have less fat, and lower muscle mass, but no
>degeneration. I'll need to do some lit searching to check whether they
>exhibit lower activity or retarded development. The fact that they are
>smaller and weaker doesn't automatically mean they are less
>active. Lower temperature is not the same thing as lower metabolic
>rate-- metabolic rate is measured as oxygen consumption per gram body
>weight.
In a congress last year I saw pictures of NIA's -- the team of Roth and
Ingram -- CR monkeys next to the controls and they looked like miserable
dwarfs. I don't think most persons are interested in going through that.
>Remember, though, the goal is learning to reproduce the improved
>oxidative stress response and improved repair mechanisms induced by CR
>without actually undergoing CR.
Sure, if you can give me CR's life extension without any side-effects, I'll
love it.
>Are you interested in aging research? If so, good for you-- it's a
>crucial question as far as health is concerned, and interesting
>from a theoretical point of view as well.
I'm a Ph.D. student in cellular senescence. I work on oxidative stress and
the telomeres.
Best wishes.
---
Joao Pedro de Magalhaes
The University of Namur (FUNDP)
Unit of Cellular Biochemistry & Biology (URBC)
Rue de Bruxelles, 61. B-5000 Namur. Belgium.
Fax: + 32 81 724135
Phone: + 32 81 724133
Reason's Triumph: http://users.compaqnet.be/jpnitya/
This archive was generated by hypermail 2.1.5 : Sat Nov 02 2002 - 08:06:56 MST