Effects of haemodialysis on active and inactive renin in nephric and anephric patients

To investigate the origin, the mechanisms of regulation and the possible biological significance of inactive renin we examined the effects of haemodialysis on plasma active and inactive (cryoactivatable) renin in four anephric and in 10 nephric patients. Before haemodialysis inactive renin was similar in anephric and in the majority of nephric patients; this suggests that the source of the inactive enzyme is predominantly extrarenal. In response to haemodialysis active renin rose significantly in nephric patients whereas inactive renin showed minor and inconsistent increments in both groups. These results indicate that the response of the inactive enzyme to haemodialysis is less than that of its active counterpart and is unaffected by the presence of the kidneys. Therefore, it appears unlikely that inactive renin represents a circulating precursor of active renin.