[Plasma prorenin as an index of prognostic evaluation in diabetes]

Plasma renin exists in an active form or as an inactive zymogen (P.P.) which is converted into active enzyme by exposure to trypsin. Inactive renin was first shown to be increased in patients with diabetes mellitus by Bye et al. The relationship between microalbuminuria (M.A.) in diabetic patients and the level of plasma inactive renin activated by trypsin was examined. The patients were divided into two groups: 1st group (Albustix+) and 2nd group (Albustix-). In the 1st group the inactive renin was greatly increased. In the patients with Albustix- albuminuria was measured by the R.I.A. method and two subgroups were identified. In the patients with albumin excretion over 40 mg/24 hr, prorenin was increased and correlated directly (r = 0.60) with M.A. In the group with albumin excretion below 40 mg/24 hr prorenin was normal except in three patients with increased M.A. These findings suggest that increased plasma prorenin levels in uncomplicated diabetes could anticipate the development of overt nephropathies.