FTO gene haplotypes are associated with GH levels in lean women
Petra Lukasova, Josef Vcelak, Marketa Vankova, Olga Bradnova, Hana Kvasnickova & Bela Bendlova
Background and aims: The fat mass and obesity associated gene (FTO) was identified as a gene with strong obesity related traits nevertheless the exact mechanism is still unknown. Our aim was to study the possible effects of FTO risk haplotype on anthropometric data and metabolic and hormonal parameters in lean women (to eliminate the influence of BMI) and to evaluate the effect of hormone contraception (HC).
Materials and methods: The SNPs rs1421085(T/C), rs1121980(G/A), rs17817449(T/G) and rs9939609(T/A) in the FTO gene were assessed by ABI TaqMan SNP Genotyping Assays; haplotypes were generated using programme PHASE. Study cohort contains 172 healthy lean women (age 26.8±7.26 years; BMI 21.5±1.99 kg/m2); 95 without HC and 77 with HC. All women were detailed anthropometrically and biochemically characterized including 3 h OGTT. The protocol was approved by the Ethic Committee. NCSS 2004 software was used for statistical analyses.
Results: The frequency of two major haplotypes was: 53.3% TGTT and 46.7% CAGA. We compared the carriers of the risk haplotype CAGA (homo- and heterozygotes) versus non-carriers (TGTT homozygotes). In lean women no influence of CAGA risk haplotype on body composition was found.
Except of increased glucagon levels we found no association of FTO variants with glucose metabolism parameters in CAGA carriers who were not using HC. Lean CAGA carriers who were using HC had higher levels of insulin and C-peptide in late phase of OGTT. The significantly raised levels of GH were detected in CAGA carriers irrespective of HC. As the HC usage alone stimulated GH levels, the HC users with the risk haplotype had 1.5 fold higher GH than HC non-users.
Conclusion: In lean control women the CAGA carrier ship as well as the usage of HC increased levels of GH.
Supported by the grant IGA MHCR NS-10209-3/2009 and NR/9839-4.