Relation between renal and hepatic excretion of drugs: III. Comparison of various methods reducing the renal or hepatic excretory capacity of rats.

In previous investigations bilateral nephrectomy (NX) and bile duct ligation (DL) were used to interrupt the renal or biliary excretion route, respectively. But competent doubt arose concerning the comparability of both interferences. In the case of DL the liver could influence the possible compensatory increase of renal excretion capacity; after removal of both kidneys such feedback on the liver is impossible. Therefore the corresponding operations were tested: bilateral ureter obstruction (UO) and so-called functional hepatectomy (fHX) caused by ligation of the porta hepatis. The time courses of a compensatory intensification of the excretory function of liver or kidney have been demonstrated. The following general conclusions can be drawn: fHX is characterized by some drawbacks because of its severe negative systemic effects. Thus DL should be preferred because the compensatory renal excretion capacity can be investigated without a significant reduction of the animal's vital forces. In contrast, NX seems to be the method of choice interrupting renal excretion. It is possible to remove both kidneys without a disturbance of other organ functions and the unpredictable effects of the hydronephrotic kidneys after UO on the whole organism are excluded. At least it is optimal to perform clearance studies approximately 24 h after both NX/UO or DL, because already at this time the phenomena of compensation have become maximal.