Endocrine Abstracts

Objective: To explore if the polymorphisms of the estrogen receptor alpha gene, XbaI (IVS1-351 A/G) and PvuII (IVS1-397 T/C) are associated with age-dependent changes in hormone levels for a better understanding of the biological actions of estrogens.

Subjects and methods: Subjects, both genders aged between 20 and 80 years were classified into two groups: reproductive age (1) and over 55 years (2). The study received the Ethical Committee approval. Morning levels of serum prolactin, estradiol, estrone, 17-OHP, DHEA, DHEAS, androstendion, progesterone, testosterone, free testosterone, DHT, SHBG, inhibin A and inhibin B, LH, FSH, TSH, GH, IGF1, insulin, cortisol, thyroid hormones, total and freePSA were measured. PvuII and XbaI polymorphisms were analyzed by PCR-RFLP.

Results: The percentages of both AA and CC genotypes significantly decreased and AG and TC genotypes increased with age. The analysis of the relationship between gene polymorphisms and circulating hormones showed significant difference in prolactin levels among genotypes only in women group. In women group of reproductive age, the polymorphisms associated with Prl (χ²=6.1/6.9), cortisol (χ²=6.6/8.78) and inhibin B (χ²=6.2); the Prl and cortisol levels were higher and inhibin B levels were lower in AG/TC genotypes; in men group, bioavailable estradiol levels were lower in AG/TC genotypes. In group over 55 yrs, (women) FSH and testosterone levels were higher and osteocalcin levels were lower in both GG and TC genotypes; in man group, PSAt and PSAf levels were higher in GG and TC genotypes.

Conclusion: In women group, variants in the ESR1 gene (AG/TC) were associated with high prolactin levels. Further researches are necessary to explain the sex specific association between these polymorphisms and the hormone levels that are related to estrogen actions.

Supported by PNII no.41-014/2007, Ministry of Education and Research.