Necrotic changes of the adrenal cortex following orthostatic collapse in rabbits.

The adreal gland was studied in 56 adult male rabbits; 44 had been subjected to orthostatic collapse, and 12 served as controls. The animals either died from collapse or were sacrificed at regular intervals up to 30 days after the experimental procedure. Nuclear pyknosis was seen in cortical cells of animals dying in collapse. At 6 or more hours following collapse, necrosis was found involving single cells, or rarely small groups of cells mainly in the zona fasciculata. Regenerative areas were present at 7 and 15 days after collapse. This necrosis may be related to a nutritive disturbance, largely hypoxic in nature (hypovolemia with blood stasis and thrombosis). The adrenal medulla showed only degranulation.