[Ultrastructural features of the kidney following administration of antidiuretic hormone].

In the course of antidiuresis induced in rats by the antidiuretic hormone injection on the background of moderate water load (in difference from the hormone injection without the water load) the expansion of the extracellular spaces and of the basal labyrinth in the epithelium of the collecting tubules and of the thin descending limb of Henle's loop was revealed; this was apparently associated with the presence of intratubular pressure gradient under the given conditions. In both the experimental versions there occurred cytoplasmic vacuolization and expansion of the interstitial cells perinuclear space in the kidney medulla. These data confirm the hypothesis on the role of the intercellular contact in the transepithelium water reabsorption path in the kidney during the urine concentration process, and indicate the participation of the interstitial cells in this process.