PURPOSE: Uncontrolled studies have shown that women with gout have hig
her serum urate concentrations and similar or lower urinary uric acid
excretion rates than do men with gout. These observations suggest a mo
re defective tubular transport of uric acid in women than in men with
gout. In this prospective study we assessed purine metabolism in women
with primary gout under controlled conditions. We also examined wheth
er there are sex-related differences in plasma and urinary purine conc
entrations among patients with primary gout. SUBJECTS AND METHODS: Ten
women with crystal-proved primary gout and normal serum creatinine le
vels (below 116 mmol/L) were studied while they were on a purine-restr
icted diet and taking no medications known to influence uric acid meta
bolism. For comparison, 20 men with primary gout and 10 women without
gout, matched for age, race, and body mass index, were studied under t
he same conditions. In each subject, plasma and 24-hour urinary uric a
cid, hypoxanthine, and xanthine concentrations were measured. The mean
of three consecutive determinations for plasma purines and five for u
rinary purines was used. Standard formulas were used to calculate the
renal clearances and the fractional excretion of purines. RESULTS: Mea
n plasma urate, hypoxanthine, and xanthine levels were significantly h
igher in women patients with primary gout compared with normal women (
P <0.05). Mean 24-hour urinary uric acid excretion was similar in both
groups. Daily urinary hypoxanthine and xanthine excretion rates were
significantly lower in gouty women patients than in control women (P <
0.05). The renal clearances and the fractional excretion of uric acid,
hypoxanthine, and xanthine were markedly lower in women with primary
gout than in control women (P <0.05). Plasma and urinary purine concen
trations were similarly increased and diminished, respectively, in wom
en and men patients with primary gout. Plasma urate, hypoxanthine, and
xanthine levels were inversely and significantly associated with the
fractional excretion of uric acid (r = -0.520; P = 0.003), hypoxanthin
e (r = -0.555; P = 0.002), and xanthine (r = -0.384; P = 0.040), respe
ctively. CONCLUSION: Women with primary gout have markedly diminished
uric acid, hypoxanthine, and xanthine excretion rates. The disturbance
of purine metabolism appears to be of a similar magnitude to that obs
erved in gouty men. The absence of significant sex-related differences
in plasma and urinary purine concentrations suggests a similar tubula
r dysfunction for purine; excretion in women and men with primary gout
.