Autoregulation of renal blood flow in the rat

Summary Renal blood flow was measured in rats anaesthetized with pentobarbital sodium by employing the PAH clearance method and the¹³³Xe washout technique. Both methods were in good agreement. In 17 rats a 25% decrement of blood pressure was attained through haemorrhage; RBF measured by PAH clearance declined by 3%, according to¹³³Xe washout by 2.7%. In further 21 rats an increase of blood pressure by an average of 265 was achieved by occlusion of the carotid arteries; RBF measured by PAH clearance declined by 3%, according to¹³³Xe washout by 1.1%. RBF was therefore almost perfectly autoregulated during both experimental manoeuvres; glomerular filtration rate (inulin clearance) was autoregulated in a similar manner. Water and sodium excretion changed in proportion to changes of blood pressure.with technical assistance of JANA HOLLYOVÁ