PREPARATION OF URINARY EXTRACTS FOR THE ALDOSTERONE ASSAY: HYDROLYSIS AND EXTRACTION1

Abstract

THE early extracts of sodium retaining material from urine were prepared by acidification of the urine to pH 1.0 or 1.5 and immediate extraction with an organic solvent (2, 7). Later on, the acid hydrolysis was prolonged for 24 hours before the urine was extracted and considerably higher results were obtained (4, 6, 10). Also β-glucuronidase was used for hydrolysis and led to increased amounts of active material when compared to those obtained after immediate extraction of the acidified urine (1, 4, 8, 9, 10). These observations indicate that aldosterone occurs in the urine to the greater part in a conjugated form. The following experiments were carried out to establish conditions of hydrolysis, which would possibly lead to a maximum recovery of the aldosterone present in the urine.