N‐Acetyltransferase Activity in the Urine in Japanese Subjects: Comparison in Healthy Persons and Bladder Cancer Patients

The activity of urinary N‐acetylamino‐transferase was determined by high‐performance liquid chro‐matographic assay of acetylisoniazid and isoniazid after administration of isoniazid to healthy Japanese male and bladder cancer patients in Japan. The healthy subjects were 47 college students and 44 company employees ranging from 18 to 64 years old (mean±SD=34.5±13.7). The bladder cancer group consisted of 58 male and 13 female patients, ranging from 28 to 82 years old (mean±SD =60.8 ±11.6), who were being treated at several hospitals. The slow phenotype, defined as an acetylation ratio (acetylisoniazid/isoniazid) of less than 2.0, was observed in 13 (14.3%) of the 91 healthy subjects, and in 20 (28.2%) of the 71 bladder cancer patients; the difference between the two groups is significant (P < 0.05). A histogram of the acetylation ratio values showed an overall leftward shift of the patient group, indicating low values of acetylation ratio in this group as a whole (P < 0.01).