[Studies on kallikrein activity in diabetic patient with hypertension caused by nephropathy]

A radioimmunoassay was performed for direct measurement of urinary active and trypsin-activatable inactive kallikreins excretion in 34 patients with Type II diabetes mellitus. (1) Diabetics showed slightly low total (inactive plus active) kallikrein excretion, normal inactive kallikrein excretion and significantly low active kallikrein excretion and active-to-total kallikrein ratio. (2) Total kallikrein excretion was normal in normotensive diabetics and hypertensive diabetics without nephropathy, low in hypertensive diabetics with nephropathy. Active kallikrein excretion and active-to-total kallikrein ratio in hypertensive diabetics were remarkably low regardless of nephropathy. (3) Para amino hippurate clearance correlated with total kallikrein excretion in normal subjects and, with active kallikrein excretion and active-to-total kallikrein ratio in both normal subjects and diabetics, but not with total kallikrein excretion in diabetics. Creatinine clearance did not correlate with total, inactive kallikrein excretions and active-to-total kallikrein ratio. (4) A positive correlation was found between fractional sodium excretion and active kallikrein excretion in normal subjects, but not in diabetics. The results suggest that reduction in ratio of active-to-total kallikrein by renal dysfunction might decrease sodium excretion in diabetics with nephropathy.