The pathophysiology of septic shock: acute renal failure in rats following live E coli injection. A histochemical study of the proximal tubules.

Acute renal failure was induced in rats by injection of a lethal dose of live Escherichia coli. Enzyme activities of the proximal tubule were studied histochemically at three, six, and 12 hours following E coli injection. The enzymes examined were alkaline phosphatase (A1Pase), acid phosphatase (AcPase), adenosine triphosphatase (ATPase), succinate dehydrogenase (SDH), glucose-6-phosphatase (G6Pase), and glucose-6-phosphate dehydrogenase (G6PDH). At three hours, ATPase activity was slightly decreased, while other enzymes showed no changes in activities at this time. At six hours, a slight increase in AcPase activity was seen in the pars recta. At this time, although A1Pase showed no change in activity, other enzymes revealed slight decreases in activities: G6Pase and SDH in the pars convoluta, ATPase in the pars convoluta and pars recta, and G6PDH in pars recta. At 12 hours after treatment, all enzymes showed decreases in activities; however, no necrotic tubule changes were detectable by light microscopy. Since sodium reabsorption in proximal tubules requires a sodium pump consisting of Na-K ATPase, early histochemical changes in ATPase activity in proximal tubule following bacteremia may be related to early changes in sodium reabsorption causing polyuria and to the subsequent development of acute renal failure.