World Hair Research

Sci. Aging Knowl. Environ., 4 August 2004
Vol. 2004, Issue 31, p. re5
[DOI: 10.1126/sageke.2004.31.re5]

REVIEWS

Murine Models of Life Span Extension

Jason K. Quarrie, and Karl T. Riabowol

The authors are in the Department of Biochemistry and Molecular Biology at the University of Calgary, Calgary, Alberta, Canada, T2N 4N1. E-mail: karl@ucalgary.ca (K.T.R.)

http://sageke.sciencemag.org/cgi/content/full/2004/31/re5

Key Words: life span extension • mouse models • growth hormone • insulin-like growth factor • oxidative damage • caloric restriction

Abstract: Mice are excellent experimental models for genetic research and are being used to investigate the genetic component of organismal aging. Several mutant mice are known to possess defects in the growth hormone/insulin-like growth factor 1 (GH/IGF-1) neurohormonal pathway and exhibit dwarfism together with extended life span. Their phenotypes resemble those of mice subjected to caloric restriction. Targeted mutations that affect components of this pathway, including the GH receptor, p66Shc, and the IGF-1 receptor (IGF-1R), also extend life span; mutations that affect IGF-1R or downstream components of the pathway decouple longevity effects from dwarfism. These effects on life span may result from an increased capacity to resist oxidative damage.

Citation: J. K. Quarrie, K. T. Riabowol, Murine Models of Life Span Extension. Sci. Aging Knowl. Environ. 2004 (31), re5 (2004)

source: http://sageke.sciencemag.org/cgi/content/abstract/2004/31/re5

—

(more…)

It seems that protein (in meat or dairy) is a stimulator of free-IGF-1

=========================

Aging Cell. 2008 Oct;7(5):681-7.
Long-term effects of calorie or protein restriction on serum IGF-1 and IGFBP-3 concentration in humans.

Fontana L, Weiss EP, Villareal DT, Klein S, Holloszy JO.

Division of Geriatrics & Nutritional Sciences, Washington University School of Medicine, St Louis, MO 63110, USA. lfontana@dom.wustl.edu

Abstract

Reduced function mutations in the insulin/IGF-I signaling pathway increase maximal lifespan and health span in many species. Calorie restriction (CR) decreases serum IGF-1 concentration by ~40%, protects against cancer and slows aging in rodents. However, the long-term effects of CR with adequate nutrition on circulating IGF-1 levels in humans are unknown.

Here we report data from two long-term CR studies (1 and 6 years) showing that severe CR without malnutrition did not change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast, total and free IGF-1 concentrations were significantly lower in moderately protein-restricted individuals. Reducing protein intake from an average of 1.67 g kg(-1) of body weight per day to 0.95 g kg(-1) of body weight per day for 3 weeks in six volunteers practicing CR resulted in a reduction in serum IGF-1 from 194 ng mL(-1) to 152 ng mL(-1).

These findings demonstrate that, unlike in rodents, long-term severe CR does not reduce serum IGF-1 concentration and IGF-1 : IGFBP-3 ratio in humans. In addition, our data provide evidence that protein intake is a key determinant of circulating IGF-1 levels in humans, and suggest that reduced protein intake may become an important component of anticancer and anti-aging dietary interventions.

Source: http://www.ncbi.nlm.nih.gov/pubmed/18843793
Full: http://onlinelibrary.wiley.com/doi/10.1111/j.1474-9726.2008.00417.x/full

=========================

(more…)