Urinary Enzyme Studies Following Renal Ischaemia in Dogs

Abstract

In recent years the analysis of urinary enzymes has attracted interest as a possible aid to the diagnosis of renal disease. We have produced renal ischaemia of varying duration in dogs and then studied the activity of different enzymes in the urine. In spite of the fact that the damage to the kidney was so small as to produce only a slight or moderate effect on creatinine clearance and inulin and PAH extraction, we observed in the first few hours following ischaemia a very marked increase in the outflow of leucineaminopeptidase (LAP), lysozyme (muramidase) and lactic dehydrogenase (LDH). The increased outflow of LAP was rapidly reduced to normal, whereas the raised values of LDH and lysozyme were observed for a longer period, 10 days to one month. After renal ischaemia LDH 5 was raised in the urine and also, for a short period immediately after, in the renal vein, indicating that this fraction in our experiments arose from damaged kidney cells. It is concluded that studies of urinary enzymes may be of greater value than the conventional renal function tests in the early diagnosis of acute renal disorders.