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Akt, AS160, metabolic risk factors and aerobic fitness in middle-aged women

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journal contribution
posted on 2010-01-01, 00:00 authored by I Levinger, Kirsten HowlettKirsten Howlett, J Peake, Andrew GarnhamAndrew Garnham, D Hare, G Jerums, Steve SeligSteve Selig, C Goodman
This study investigated the association between the basal (rest) insulin-signaling proteins, Akt, and the Akt substrate AS160, metabolic risk factors, inflammatory markers and aerobic fitness, in middle-aged women with varying numbers of metabolic risk factors for type 2 diabetes. Methods: Sixteen women (n=16) aged 51.3±5.1 (mean ±SD) years provided muscle biopsies and blood samples at rest. In addition, anthropometric characteristics and aerobic power were assessed and the number of metabolic risk factors for each participant was determined (IDF criteria). Results: The mean number of metabolic risk factors was 1.6±1.2. Total Akt was negatively correlated with IL-1β (r = -0.45, p = 0.046), IL-6 (r = -0.44, p = 0.052) and TNF-α (r = -0.51, p = 0.025). Phosphorylated AS160 was positively correlated with HDL (r = 0.58, p= 0.024) and aerobic fitness (r = 0.51, p=0.047). Furthermore, a multiple regression analysis revealed that both HDL (t=2.5, p=0.032) and VO2peak (t=2.4, p=0.037) were better predictor for phosphorylated AS160 than TNF-α or IL-6 (p>0.05). Conclusions: Elevated inflammatory markers and increased metabolic risk factors may inhibit insulin-signaling protein phosphorylation in middle-aged women, thereby increasing insulin resistance under basal conditions. Furthermore, higher HDL and fitness levels are associated with an increase AS160 phosphorylation, which may in turn reduce insulin resistance.

History

Journal

Exercise immunology review

Volume

16

Pagination

98 - 104

Publisher

Human Kinetics

Location

Champaign, Ill.

ISSN

1077-5552

Language

eng

Notes

Reproduced with the specific permission of the copyright owner.

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2010, Human Kinetics