Alterations in Intrarenal Blood Flow Distribution

Various methods used to measure the intrarenal distribution of blood flow are evaluated. Evidence is presented that para-aminohippurate (PAH) extraction cannot be utilized to measure noncortical blood flow. The inert-gas methods can be used as an index of total cortical blood flow, but cannot further discriminate changes in regional blood flow in the kidney. Although rheological effects independent of changes in regional blood flow cannot be totally excluded, the data accumulated to date strongly suggest that the radioactive-microsphere method is a valid marker of particulate distribution in various areas of the renal cortex. The use of antiglomerular basement membrane antibody to measure plasma flow distribution is discussed.

Studies were performed in which the distribution of cortical blood flow was measured in several acute models with varying effects on urinary sodium excretion. These studies demonstrate that the distribution of renal cortical blood flow is not necessarily correlated with changes in sodium excretion, but rather with alterations in renal resistance.