SHBG Gene Promoter Polymorphisms In Men Are Associated With Serum Sex Hormone-binding Globulin, Andr

Discussion in 'Scientific Studies' started by Drareg, Nov 20, 2016.

  1. Drareg

    Drareg Member

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    This interesting in relation to the femur bone growth.

    SHBG gene promoter polymorphisms in men are associated with serum sex hormone-binding globulin, androgen and androgen metabolite levels, and hip bone mineral density.


    Abstract
    CONTEXT:
    SHBG regulates free sex steroid levels, which in turn regulate skeletal homeostasis. Twin studies have demonstrated that genetic factors largely account for interindividual variation in SHBG levels. Glucuronidated androgen metabolites have been proposed as markers of androgenic activity.

    OBJECTIVE:
    Our objective was to investigate whether polymorphisms in the SHBG gene promoter [(TAAAA)(n) microsatellite and rs1799941 single-nucleotide polymorphism] are associated with serum levels of SHBG, sexsteroids, or bone mineral density (BMD) in men.

    DESIGN AND STUDY SUBJECTS:
    We conducted a population-based study of two cohorts of Swedish men: elderly men (MrOS Sweden; n congruent with 3000; average age, 75.4 yr) and young adult men (GOOD study; n = 1068; average age, 18.9 yr).

    MAIN OUTCOME MEASURES:
    We measured serum levels of SHBG, testosterone, estradiol, dihydrotestosterone, 5alpha-androstane-3alpha,17beta-diol glucuronides, androsterone glucuronide, and BMD determined by dual-energy x-ray absorptiometry.

    RESULTS:
    In both cohorts, (TAAAA)(n) and rs1799941 genotypes were associated with serum levels of SHBG(P < 0.001), dihydrotestosterone (P < 0.05), and 5alpha-androstane-3alpha,17beta-diol glucuronides (P < 0.05). In the elderly men, they were also associated with testosterone and BMD at all hip bone sites. The genotype associated with high levels of SHBG was also associated with high BMD. Interestingly, male mice overexpressing human SHBG had increased cortical bone mineral content in the femur, suggesting that elevated SHBG levels may cause increased bone mass.

    CONCLUSIONS:
    Our findings demonstrate that polymorphisms in the SHBG promoter predict serum levels of SHBG, androgens, and glucuronidated androgen metabolites, and hip BMD in men.

    Comment in
     
  2. Mito

    Mito Member

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    rs1799941 is a SNP of the SHBG gene. It is significantly associated with sex-hormone binding globulin (SHBG) levels as well as sex hormone regulation.

    ''A'' allele was associated with increasing testosterone levels in men (P= 8.11 × 10−6) [R].

    Subjects with the ''A'' allele (GA+AA) had a trend for lower free estradiol index (FEI) compared to the GG genotype (p=0.04) [R].

    Each copy of the ''A'' allele is associated with a 0.20 SDs increase in sex hormone binding globulin (SHBG) levels [R].

    Carriers of the minor allele ''A'' had higher circulating SHBG, independently of sex, age, and total body fat (P = 0.025) [R1, R2].
     
  3. ddjd

    ddjd Member

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    @Drareg @Mito

    Thanks for posting this guys. I suspected my SHBG might be the reason for my high estrogen levels and T3 causing Estrogenic symptoms.

    Checked my 23andme and I'm "G/G" so does that mean I have low SHBG?
     
  4. Mito

    Mito Member

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    No it just means you have the most common form of that SNP which is not associated with higher levels of SHBG.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2742399/

    6F68C6DF-D801-472A-A2DC-DCAB2407A9A1.jpeg
     
  5. ddjd

    ddjd Member

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