ENDOTHELIN PRODUCTION IN THE RABBIT COLLECTING DUCTS OF ACUTE-RENAL-FAILURE MODELS - AN IMMUNOHISTOCHEMICAL STUDY

Endothelin 1 (ET-1) production was examined in the rabbit nephron in a cute renal failure (ARF) induced by uranyl acetate administration or b y clamping the renal artery. Uranyl acetate dissolved in saline was in jected intravenously at a dose of 0.8 mg/kg (n = 12). In the ischemic kidney experiment, 60 min of left renal artery clamping was carried ou t 1 week after removing the right kidney (n = 8). Plasma and urine con centrations of ET-1 were measured 0, 24, and 48 h after treatment, and immunohistochemical studies of renal tissues obtained 48 h after the experiments were carried out using ET-1 monoclonal antibody. The fract ional excretion of ET-1 increased from 10 to 89% at 48 h in the uranyl acetate treated group and from 6 to 15% at 24 h in the renal artery c lamping group, suggesting the existence of ET-1 secretion from the nep hron in both types of ARF. By immunohistochemical examination, strong ET-1 expression was noted only in the collecting ducts. No staining wa s observed in other parts of the nephron in both types of ARF. The pre sent study indicates that the increased expression of ET-1 probably re flects production by the collecting ducts in both rabbit ARF models.