On human tissue kallikrein activity in urine of Brazilian White and Black primary hypertensive patients.

OBJECTIVE To evaluate the possible relationship between the human tissue kallikrein amidase activity with sex and ethnicity in Brazilian primary hypertensive patients. DESIGN Population-based study. PARTICIPANTS One hundred men and women, Black and White primary hypertensive patients aged 20 years and older were selected. Eighty nine healthy individuals, paired according to age, sex, and ethnics were used as controls. METHODS Early-morning midstream urine was used. Human tissue kallikrein amidase activity was estimated with D-Val-Leu-Arg 4-nitroanilide substrate. Creatinine was determined by a method based on Jaffe's reaction. hK1 amidase activity is expressed in microM/(min x mg creatinine) to correct for differences in urine flow rate. Data are expressed as medians. RESULTS Human tissue kallikrein amidase activity was significantly lower in the urine of hypertensive patients (0.210 microM/(min x mg creatinine) than in the urine of control subjects (0.260 microM/(min x mg creatinine) (P = .010). This result supports data from the literature. Contrasting to what was already reported, namely that human tissue kallikrein excretion is higher in females than in males, and especially higher in Caucasians than in African Americans, our results show that, in the urine of Brazilian hypertensive patients and control subjects, no significant effect of sex and ethnicity on human tissue kallikrein amidase activity was observed. CONCLUSIONS The lack of ethnicity effect supports what was already asserted, namely, that, in Brazil, at an individual level, color, as determined by physical evaluation, is a poor predictor of genomic African ancestry, estimated by molecular markers.