TITLE:
Association between IGF-2 gene and fat-free mass in response to resistance training
AUTHORS:
Andréa Carmem Guimarães, Rinaldo Wellerson Pereira, Ricardo Moreno Lima, Michel Santos Silva, Victor Machado dos Reis, Nuno Domingos Garrido, Romulo Maia, Ricardo Jacó de Oliveira
KEYWORDS:
Fat-Free Mass; Fat Mass; Resistance Training; Muscle Strength; IGF-2 Polymorphism; Elderly
JOURNAL NAME:
Health,
Vol.5 No.6,
June
11,
2013
ABSTRACT: BACKGROUND: It is well established that the human aging
process is associated with a significant decline in neuromuscular function
and performance. Twin studies demonstrate that genetic factors partially
explain the inter-individual variation of fat-free mass (FFM) and muscle
strength. PURPOSE: To examine the association between the polymorphism of the
gene IGF-2 with phenotypes strength and muscle mass of elderly women pre and
post resistance training. METHODS: 76 elderly women participated in this
analysis. These volunteers, who should be sedentary for at least 6 months
before the study, were assigned four groups in relation to allele GAGG, AA,
GAAA and GG. The first analysis compared 60 elderly women with GG and GA allele
(GAGG) versus 16 elderly women with AA allele. The second analysis compared 54
elderly women with GA and AA (GAAA) versus 22 elderly women GG allele. The Body
mass index, fat free mass, fat mass and Isokinetic Muscle Peak Torque were
measured. All volunteers were participating in the Resistance Training program.
The DNA was extracted from peripheral venous blood leukocytes using a salting
out protocol. The primer for IGF-II gene exon 9 was 5’-GTCCCTGAACCAGCAAAGAG-3’ 0.5 μM (0.625 μl) Primer
R-5’-TGATGGAAAAGGGAGTGAGG-3’ 0.5 μM (0.625 μl), Taq DNA Polimerase enzime 0.5 U
(0.1 μl), água milli-Q (3.8 μl) 5 hg de DNA (3 μl). PCR amplification was performed
in a programmable thermal cycler GeneAmp? PCR System 9700. RESULTS:
The results of the first analysis GAGG × AA versus the group AA showed the
relative increase in knee extensor peak torque relative and also in the
fat-free mass and showed a decrease in the fat mass percentage in the GAGG
group. The second analysis considered the group GAAA versus group GG showed
decreases in the fat-free mass percentage in the GAAA group, also showed the
relative increase in the fat-free mass in the GG group and decrease in the fat
mass percentage in the GG group. CONCLUSIONS: The results of this study show
that 24 weeks of the resistance training improved strength and muscle mass and
decreased the fat mass. The results confirm this assertion and suggest the G
allele presents more influence over the A allele, in
relation to phenotypes strength and muscle mass in elderly women after
resistance training.