ABSTRACT
OBJECTIVE: To investigate the CYP3A activity and its characteristics of distribution in the pre-school children in Xiamen. METHODS: Using hydrocortisone as a noninvasive probe, urine concentrations of hydrocoritisone ydrocortisone and 6β-hydroxycortisol were determined by HPLC method. The urinary ratio of 6β-hydroxycortisol/hydrocortisone was used to quantify CYP3A activity. RESULTS: The CYP3A activity in the 287 healty children showed a skewed to the left distribution. The median value was 2.61 and the value of quartile range was 3.97. CONCLUSION: There is no significant difference in CYP3A activity in gender. With increasing of ages, the CYP3A activity shows the decreasing tendency. The results show a statistic correlation between the ages and CYP3A activity. The value of CYP3A activity in age 3 group is higher than age 4 group.