Active and Inactive Renin after SQ 14225 (Captopril) Administration

The changes of active and inactive renin in plasma after the oral administration of 25 mg or 50 mg of SQ 14225 (Captopril) were studied in 29 hypertensive patients. Inactive renin was calculated as plasma renin activity (PRA) after cold storage minus PRA before cold storage. The patients were divided into 2 groups, responders and non-responders, according to the response of active renin to Captopril. In 9 responders, the active renin increased markedly while the inactive renin decreased. On the other hand, in 20 non-responders, both renin activities increased only slightly. These results suggest that inactive renin may be converted in vivo to active renin by Captopril.