X-Message-Number: 26669
Date: Wed, 20 Jul 2005 05:24:13 -0700 (PDT)
From: Doug Skrecky <>
Subject: Insulin and longevity

[The key effect here might the suppressive effect of insulin on
autophagy.]

Biogerontology. 2003;4(5):297-307.
Insulin and longevity: antidiabetic biguanides as geroprotectors.
  The results of previous experimental studies of effects of
antidiabetic biguanides (phenformin and buformin) on life span and
spontaneous tumor incidence in mice and rats were recalculated and
reanalyzed using standard demographic models of mortality. The
chronic treatment of female C3H/Sn mice with phenformin prolonged
the mean life span by 21.1% (P < 0.05), the mean life span of the
last 10% survivors by 28.4% and the maximum life span by 5.5 months
(by 26%) in comparison with the control. The demographic aging rate
represented by the estimate of respective Gompertz's parameter
decreased by 31.2% and MRDT increased 1.45-fold. The treatment
significantly inhibited (4.0-fold, P < 0.01) the incidence of
mammary adenocarcinomas in mice. Administration of phenformin to
female LIO rats failed to influence the mean life span. At the same
time, the mean life span of the last 10% survivors increased by
10.1% (P < 0.05), and maximum life span increased by 3 months (+9.8%).
Phenformin attenuated the development of spontaneous tumors in
comparison to the control. The treatment of female rats with another
antidiabetic biguanide, buformin, slightly increased their mean life
span (by 7.3%; P > 0.05). The mean life span of the last 10%
survivors increased by 12% (P < 0.05) and the maximum life span
increased by 2 months (+5.5%) as compared with controls. The
population aging rate decreased by 18.1% (P < 0.05) and MRDT
increased 1.22-fold under the influence of buformin (P < 0.05). The
total tumor incidence decreased by 49.5% in buformin-treated rats.
Both antidiabetic biguanides slightly decreased the body weight,
slowed down the age-related decline of the reproductive function in
female rats. The results of our experiments provide evidence that
antidiabetic biguanides are promising geroprotectors as well as
drugs which can be used in the prevention of cancer.

Vopr Onkol. 1980;26(6):42-8
[Effect of buformin and diphenylhydantoin on the life span, estrous
function and spontaneous tumor incidence in rats]
  Chronic treatment of female rats with buformin (k mg/day per rat)
is shown to decrease the body weight, to increase the average life
span by 9% and to reduce the incidence of spontaneous tumors. The
administration of diphenylhydantoin (7.5 mg/day per rat) would not
change these parameters. The treatment of rats with buformin and
diphenylhydantoin was also found to prolong their reproductive
period and to reinitiate regular estrous cycles in persistent
estrous rats.

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