[Ultrastructural study of the interstitial cells of the internal kidney medulla exposed to indomethacin].

Unusual cylindrical bodies-megatubules, which get in touch with lipid granules with granular endoplasmatic reticulum among themselves and with the pores of the nuclear and cellular membrane, are described in the interstitial cells of the kidneys of the control rats. After a suppression of prostaglandin synthesis with indomethacin (5 mg/kg venously of intraperitonealy per day for 6 days) there was statistically significant increase of the mass of the compact lipids in the interstitial cells (hypergranulation as the volume of the granule was preserved) - a proof that the granules contained precursors of renal prostaglandins. The nuclei were presented with round contours, while the perinuclear spaces were narrowed.

[Structural organization of the tubular system of the internal renal medulla interstitial cells].

The tubular system of renal medulla interstitial cells includes multitubular complexes, mucrotubules and megatubules. Multitubular complexes are compact masses consisting of dozens of crosscut thin-walled tubular lumens. Megatubules are 2500 A in diameter, up to 5.