Volume changes in the rat renal cortex during urography.

At different periods of urography rat kidney were instantly frozen at -165 degrees C. Using appropriate histological techniques and planimetry of different cortical compartments and fractions the structural background of renal cortical volume variations during urography was elucidated. The renal cortex reacted to intravenous injection of hypertonic contrast medium with an immediate increase of volume, followed by a decrease from 30 to 60 seconds. Measuring the volume shares of different cortical compartments, the complex nature of cortical volume variations during the first minutes of urography could be demonstrated. Subdivision of the tubular compartments into cellular and luminal fractions showed even greater complexity of volume variations. All the major cortical volume changes came to an end approximately three minutes after the injections.