Endocrine changes and urinary citrate excretion.

Urinary citrate affects the ion-activity products of calcium oxalate and calcium phosphate and inhibits the growth of these crystals. Women are less prone to develop calcium stones and because they also excrete more citrate than men, an effect of sex steroids on citrate excretion might be important. We therefore analysed urinary citrate and creatinine before and during treatment with estrogen alone or together with medroxyprogesterone acetate in 29 postmenopausal women and at different gestational ages in 19 pregnant women. Urinary citrate and creatinine was also determined before and after orchidectomy in ten men with carcinoma of the prostate. The excretion of citrate and the ratios between citrate and creatinine were not significantly altered by pregnancy or orchidectomy. Neither did treatment with estrogen or estrogen/medroxyprogesterone acetate affect these variables. We were unable to explain the difference in citrate excretion between men and women by effects of sex steroids.