Effect of long-term administration of cross-sex hormone therapy on serum and urinary uric acid in transsexual persons

J Clin Endocrinol Metab. 2008 Jun;93(6):2230-3. doi: 10.1210/jc.2007-2467. Epub 2008 Mar 18.


Background: Transsexual persons afford a very suitable model to study the effect of sex steroids on uric acid metabolism.

Design: This was a prospective study to evaluate the uric acid levels and fractional excretion of uric acid (FEUA) in a cohort of 69 healthy transsexual persons, 22 male-to-female transsexuals (MFTs) and 47 female-to-male transsexuals (FMTs). The subjects were studied at baseline and 1 and 2 yr after starting cross-sex hormone treatment.

Results: The baseline levels of uric acid were higher in the MFT group. Compared with baseline, uric acid levels had fallen significantly after 1 yr of hormone therapy in the MFT group and had risen significantly in the FMT group. The baseline FEUA was greater in the FMT group. After 2 yr of cross-sex hormone therapy, the FEUA had increased in MFTs (P = 0.001) and fallen in FMTs (P = 0.004). In MFTs, the levels of uric acid at 2 yr were lower in those who had received higher doses of estrogens (P = 0.03), and the FEUA was higher (P = 0.04). The FEUA at 2 yr was associated with both the estrogen dose (P = 0.02) and the serum levels of estradiol-17beta (P =0.03). In MFTs, a correlation was found after 2 yr of therapy between the homeostasis model assessment of insulin resistance and the serum uric acid (r = 0.59; P = 0.01).

Conclusions: Serum levels of uric acid and the FEUA are altered in transsexuals as a result of cross-sex hormone therapy. The results concerning the MFT group support the hypothesis that the lower levels of uric acid in women are due to estrogen-induced increases in FEUA.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / analysis
  • Dose-Response Relationship, Drug
  • Estradiol / blood
  • Female
  • Follow-Up Studies
  • Gonadal Steroid Hormones / administration & dosage
  • Gonadal Steroid Hormones / therapeutic use*
  • Humans
  • Insulin / blood
  • Insulin Resistance
  • Male
  • Time Factors
  • Transsexualism / blood
  • Transsexualism / drug therapy*
  • Transsexualism / urine
  • Uric Acid / blood*
  • Uric Acid / urine*


  • Blood Glucose
  • Gonadal Steroid Hormones
  • Insulin
  • Uric Acid
  • Estradiol