Low Plasma glucose does not explain CR

[Guest guest]

Looks like you are going to have to look elsewhere than plasma glucose to understand how CR works. I like this research, because it shows how the whole "glycation" perspective on aging is, while interesting, perhaps of somewhat limited utility for a more comprehensive elucidation of the phenomenology of aging.

What is particularly important here is that, in the full-text, the authors state specifically that the survival of GLUT-4 transgenic mice, which have constitutively lower plasma glucose, was not increased as seen in CR.

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http://www.sciencedirect.com/science/journal/01974580

Early hypothalamic response to age-dependent gene expression by calorie restriction

Chunxiao Fua, Liang Xia, Mcb, Morgen Hickeya and Eun-Soo Hana, , aDepartment of Biological Science, The University of Tulsa, 600 S. College Ave., Tulsa, OK 74104, USAbCenter for Developmental and Health Genetics, The Pennsylvania State University, 101 Amy Gardner House, University Park, PA 16802, USA Received 28 February 2005; revised 31 May 2005; accepted 16 June 2005. Available online 26 July 2005.

Abstract

Molecular events linking the initial detection of calorie restriction (CR) to changes in gene expression throughout the organism that ultimately retard aging in CR animals are unknown. This study measured changes in gene expression induced by CR and by aging in the hypothalamus, which likely plays a central role in the initial perception of and response to CR. Hypothalamic expression profiling was done in young (4–6 months) ad libitum fed (AL), young CR (2.5–4.5 months of CR), and old (26–28 months) AL male C57BL/6 mice. CR altered the expression of 137 genes and aging altered 1222. Only 8 age-related genes were oppositely regulated by CR. To test whether reduced plasma glucose is a signal in altering hypothalamic gene expression, we examined GLUT4 transgenic mice (C57BL/6 background; 4–6 months), which have reduced plasma glucose similar to that of CR mice. Twenty-seven genes differed between transgenic and non-transgenic mice; nine of these were only altered by CR. The decreased

plasma glucose had a limited role in CR mediated hypothalamic gene expression. Keywords: Gene expression; Calorie restriction; Aging; Hypothalamus; GeneChip; GLUT4 transgenic mice

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T.

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