IL6 and acute kidney injury: To further test the hypothesis that circulating IL-6 is filtered and appears in the urine during AKI, we examined the fate of recombinant human IL-6 (hIL-6) injected intravenously to mice five hours after vehicle injection, furosemide injection (pre-renal azotemia), sham operation, ischemic AKI, or bilateral nephrectomy.