ABSTRACT
Electron microscopic and morphometric investigations of the rat kidneys in 3-6 days after a complete fasting have revealed certain ultrastructural signs of an increased proteolysis in the proximal parts of the nephron canaliculi and structural manifestation in the glomerular blood stream changes, that represents an important condition for passing proteins the glomerular membrane. In this connection, it is supposed that at adaptation to fasting the kidney ensures proteolysis of endogenic-proteins--the first stage of their reconstruction. This function is ensured by structural-functional reconstruction of the juxtaglomerular complex, vessels of the filtrative apparatus and by the proteolytic system in the proximal part of the nephron canaliculus.