The distribution of intrarenal blood flow has been measured using the 133Xe-washout technique in thirteen baboons 2 weeks after ligation of the common bile duct. 2. In comparison with eight sham-operated baboons, there was a signifigant decrease in the percentage distribution of blood to the cortex, although the rate of flow was unchanged. These changes were accompanied by a significantly increased flow rate and percentage distribution of flow through the juxtameduallary circulation. 3. In a further five baboons treated in the same way, various doses of noradrenaline were infused into the renal artery. In these animals there was an enhanced pressor response to noradrenaline, and this effect was completely abolished by an alpha-adrenoreceptor blocking agent (phenoxybenzamine). The beta-adrenoceptor blocking drug (propranolol) had no such effect. 4. This enhanced response was not seen when noradrenaline was infused into three sham-operated baboons. 5. These observations suggest that the alterations in renal perfusion in obstructive jaundice may be due to an increase renovascular sensitivity to circulating catecholamines and an enhanced alpha-adrenoceptor activity.
