Effect of Long-Term Administration of Hormonal Therapy on Serum and Urinary Uric Acid

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 theMFTgroup. 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-17 beta (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: Serumlevels of uric acidandtheFEUAare 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 inwomenaredueto estrogen-induced increases in FEUA.

(J Clin EndocrinolMetab 93: 2230–2233, 2008)

Télécharger le PDF