Urinary Excretion of Lithogenic Substances and Inhibitory Activity Towards Calcium-Oxalate-Monohydrate Crystal Growth in Idiopathic Urolithiasis

Calculus formation occurs in urine supersaturated with Ca, oxalate (Ox), phosphate (Pi), and uric acid (UA) (1). The calculated degrees of supersaturation have been used to estimate risk factors for the probably formation of renal stones. Normal urine contains a variety of inhibitory substances which may prevent or retard the precipitation of these lithogenic substances in the urinary tract. These inhibitors include components like citrate, isocitrate, pyrophosphate, magnesium polyacidic peptides, and a variety of polyanionic compounds as well. The present study is concerned with the inhibitory activity (IA) and urinary excretion of lithogenic substances, and examines possible correlations between urinary UA levels and urinary inhibitory activity towards CaOx-monohydrate (COM) crystal growth.