INFLUENCE OF POLYMORPHISMS IN THE 17??hyphen;HSD1 GENE ON BMD AND SERUM ESTRADIOL IN YOUNG WOMEN

Abstract

The 17β-hydroxysteriod dehydrogenase 1 (17β-HSD1) gene encodes the 17β-HSD type 1 enzyme that catalyzes the reaction converting estrone to estradiol. PURPOSE: This investigation was conducted to test the hypothesis that the A/A genotype of 17β-HSD1 would be associated with elevated levels of bone mineral density (BMD) and serum estradiol (E2) in college-aged young women. METHODS: Forty-six young women aged 21.0±3.0 years (X±SD) participated in this investigation. 17β-HSD1 genotype was determined by PCR as A/A, A/G, or G/G. BMD was assessed at the spine (SP) and proximal femur (femoral neck (FN), total hip (TH)) by dual energy x-ray absorptiometry (DXA). In the subjects who ovulated, fasting serum E2 was determined by radio-immuno assay (RIA) on samples obtained on day 22 of the menstrual cycle. Weekly physical activity patterns during the year prior to testing were based on data derived from questionnaires. BMD and E2 differences between women of the differing genotypes were determined by multivariate analysis of variance (with ethnicity, weight, gynecologic age and normalized minutes of physical activity as the covariates for BMD). RESULTS: Results are presented below as X±SD. *Significant difference between the group homozygous for the A allele (N = 11) and the group including those heterozygous or homozygous for the G allele (N = 35, p < 0.05).TableWhile luteal phase E2 concentrations did not differ between the genotypes, BMD was significantly greater in those homozygous for the G allele. CONCLUSION: The above results suggest 17β-HSD1 genotypes may be an important determinant of BMD in young women. Supported by USC James H. Zumberge Faculty Research and innovation Fund, USC MFWA Research Fund, and BCRP 1KB-0060