Effect of Oestrogen Therapy

Uric acid clearance studies were carried out on a lowpurine diet in 22 trans-sexual men before and during oestrogen therapy for this condition (stilboestrol in 21 cases, ethinyloestradiol in one). Plasma uric acid fell in 15 of the subjects and urinary uric acid rose in 17 of 20 subjects in whom satisfactory collections were obtained. These changes are significant and it is suggested that hormonal influences are responsible for the known age and sex differences in plasma uric acid. during treatment 4'1 mg/100 ml (± S.D. 0-9). This fall is significant (t test for paired differences, P < 0-01; fig. 1). Urinary uric acid rose in 17 of20 subjects in whom satisfactory collections were obtained, the mean value before treatment of 414 mg/24 hr (I S.D. 104) rising to 529 mg/24 hr (± S.D. 100). Uric acid clearance rose in 17 of the 20 subjects, from a mean value of 6-3 ml/min (± S.D. 1-8) to 9'1 ml/min (+ S.D. 2-8). These again are highly significant changes (P < 0-001, figs. 2 and 3). There was no correlation between fall in plasma uric acid or rise in urinary uric acid and the dosage of oestrogen; most of the subjects were taking 20 mg of stilboesterol daily, and only two were taking very low or very high doses. Owing to a technical error with loss of samples, results of plasma and urinary creatinine estimations were available in only