Reliability of the measurement of intrarenal haemodynamics in the dog, as determined by the radioactive microsphere technique.

In the anaesthetized dog total renal blood flow (RBF) and its intrarenal distribution were investigated by the radioactive microsphere technique under control conditions and after various experimental interventions. (i) In five control series performed within the last four years, there was a small but significant scatter in total RBF, due entirely to changes in inner cortical (IC) perfusion, while outer cortical (OC) perfusion proved to be constant. (ii) Repeated measurements in the same dog, performed after 1 h interval revealed constancy of total RBF with some inward shifting in cortical perfusion. (iii) Surgical intervention or manipulation of the kidney did not alter total RBF but led to an increase in IC, compensated by a decrease in OC perfusion (iv) The possible role of local intrarenal hormones (angiotensin and prostaglandin) in the above changes is discussed.