ULTRASTRUCTURAL-CHANGES IN RAT-KIDNEY MITOCHONDRIA IN RESPONSE TO THEOXYGEN-PARADOX OR CALCIUM-PARADOX

Isolated, perfused rat kidney released lactate dehydrogenase in respon se to the protocol of a standard oxygen-paradox or calcium-paradox. Th e results are comparable to those found with rat heart. The mitochondr ia of the proximal tubule cells at the end of the calcium-paradox were swollen, had mitochondrial bars and were subdivided with internal sep ta; after the oxygen-paradox they exhibited, in addition, many myelin figures. Such ultrastructural changes were characteristic of the mitoc hondria of skeletal and cardiac muscles damaged by a rise in [Ca2+](i) . It is concluded (i) that typical calcium- and oxygen-paradoxes can b e produced in kidney, (ii) that these are associated with a rise in [C a2+](i) and (iii) the proximal tubules, in particular, are damaged.