Physiological and pharmacological intervention for the purpose of determining organ functional reserve is a familiar concept in medical testing and in nuclear medicine. Nephrourologic applications include established procedures such as diuretic scintigraphy for determination of urinary outflow obstruction and captopril scintigraphy for determination of renovascular hypertension. Subtle renal dysfunction may exist among some individuals with essential hypertension, induced by provocative exercise renography, and not observed at rest. The strength of nuclear medicine resides in its ability to assess disorders of organ function for the diagnostic, prognostic, or pathophysiological information provided. Nephrourologic interventions are reviewed with an emphasis on the functional changes caused by the intervention.