Renin Release and Renal Cortical Ischemia Following Aortic Cross Clamping

Previous investigators demonstrated marked changes in renal blood flow following infrarenal aortic clamping. More recent reports, however, have disagreed with these earlier results. The present experiments have confirmed the fact that a major shift in total renal blood flow does not occur coincident with aortic cross clamping. However, a substantial shift in the ratio of cortical to medullary flow does occur. The observation that renal vein renin levels were elevated by aortic clamping suggested a causal role of the renin angiotensin system in producing the observed blood flow alterations. These hemodynamic changes were blocked by prior administration of propranolol hydrochloride, a β-adrenergic antagonist that also blocked renal renin release.