URINARY KALLIKREIN EXCRETION IN TYPE-1 (INSULIN-DEPENDENT) DIABETES-MELLITUS

Kidney haemodynamics appear to change after the early phases of diabet ic nephropathy: increases in glomerular filtration rate and in renal p lasma flow have been widely reported, while kidney size is increased. As the renal kallikrein-kinin system has been demonstrated to regulate kidney blood circulation, we have evaluated the excretion of urinary kallikrein in 87 Type 1 (insulin-dependent) diabetic patients with and without hyperfiltration. Urinary kallikrein excretion was measured in 24-h urine collections. The esterolytic activity was determined by fl uorimetric assay. The excretion of urinary kallikreins was significant ly higher in hyperfiltering patients (472 +/- 125 esterase units/24 h) than in normofiltering (168 +/- 77 esterase units/24 h) and control s ubjects (151 +/- 39 esterase units/24 h), p < 0.001. Furthermore, we o bserved a positive correlation between urinary kallikrein excretion an d glomerular filtration rate (r = 6.785). These data suggest that vari ations of kallikrein and kinin concentrations may play a role in the a lteration of renal haemodynamics in Type 1 diabetes. It is possible th at the kinin-kallikrein system. the renin-angiotensin system and the p rostaglandins may interact to determine the haemodynamic alterations w hich arc present in the diabetic discase.