cron-web.org

[A1CR]

Much CR/CRON-related information is apparently in the below
paper.

Faulks SC, Turner N, Else PL, Hulbert AJ.
Calorie restriction in mice: effects on body composition,
daily activity,
metabolic rate, mitochondrial reactive oxygen species
production, and
membrane Fatty Acid composition.

J Gerontol A Biol Sci Med Sci. 2006 Aug;61(8):781-94.

PMID: 16912094 http://tinyurl.com/pt4lk


Abstract:

Different levels of calorie restriction (CR) (125, 85, 50,
or 40 kcal/wk for 1, 3, and 6 months) were examined in mice
by using the paradigm of Weindruch and colleagues. Lean and
total body mass increased on 125 and 85 kcal/wk, but there
was negligible growth on low-energy intake. There was no
CR-induced reduction in either daily activity or
mass-specific metabolic rate. There was no CR-effect on in
vitro reactive oxygen species production by liver or muscle
mitochondria at 3 months, but after 6 months the effect was
significantly reduced in liver mitochondria from 40 kcal/wk
mice compared to 125 kcal/wk mice. Changes in the fatty acid
composition of phospholipids from liver, kidneys, heart,
brain, and skeletal muscle were observed following 1 month
of CR.


Excerpts:


... "live fast-die young" perspective inherent in the
rate-of-living
theory of aging, many investigators initially thought that
the life
span-extending properties of CR were due to it reducing the
mass-specific
rate of metabolism. ... CR in rats does not reduce their
mass-specific
metabolic rate ... mass-specific metabolic rate appeared to
increase over
the 6 months ... energy expenditure of CR rats is higher
than predicted from
their altered body composition [http://tinyurl.com/kh8z4 ]
Not only did CR not reduce resting metabolic rate but it
also did not reduce daily activity and thus presumably daily
energy
expenditure. This lack of a decrease in mass-specific
metabolism during CR
would appear to be a general phenomenon in that dietary
restriction in both
wild-type and the long-living CHICO-mutant strain of D.
melanogaster also
did not result in a change in mass-specific rate of
metabolism [the not
pdf-availed http://tinyurl.com/gbzvn ]. It is clear that the
life-span
extension due to CR is not due to a decrease in the
mass-specific
rate-of-living.

....... decrease in the relative content of ... docosahexaenoic
acid ...
compensated by an increase in the relative content of
peroxidation-resistant
monounsaturated ... decrease ... in peroxidation-prone
arachidonic acid ...
increase ... peroxidation-resistant linoleic acid .... Insulin,
triiodothyronine, and growth hormone ... lowered by CR (1)
..... PI of liver
mitochondrial phospholipids of different mammal and bird
species has been
shown to be inversely related to maximum life span ... 24%
decrease in the
PI (and thus peroxidation susceptibility) of liver
mitochondrial membrane
lipids was associated with a doubling of life span
[http://tinyurl.com/f8tmp that was previous described in
http://tinyurl.com/zvs7f as well as other messages that can
be searched for
with PMID: 15757684 in our old archives]. It has been
speculated that one of the mechanisms by which CR extends
life span is by lowering the PI of membrane phospholipids