1. The effect of propranolol on total and regional renal blood flow was measured in conscious rabbits after 6 days on normal or low sodium diets.
2. Propranolol inhibited the fall in total superficial cortical renal blood flow which occurred in response to the low sodium diet but did not influence renal blood flow in rabbits on a normal sodium diet.
3. Reduction and redistribution of renal blood flow in response to a low sodium diet appears to be mediated by a beta-receptor mechanism and may be a consequence of intrarenal release of renin.