Mitochondrial alterations in aged rat adrenal cortical cells.

Mitochondrial alteration in aged rat adrenal cortical cells were studied. Severe mitochondrial alterations were predominantly observed in the zonae fasciculata and reticularis of the adrenal cortex. Many adrenal cortical mitochondria from these zones were relatively larger in size and more irregular in shape. The matrix of altered mitochondria appeared denser than normal and the intramitochondrial cristae including myelin-like membrane configurations and parallel arrays were seen. Intramitochondrial inclusions such as paracrystalloid structures were also noted. In addition, giant mitochondria with various inclusions such as highly electron dense lipid-like materials, large vacuoles and other cytoplasmic organelles including small mitochondria were characteristically observed. Based on these data, functional aspects of the altered mitochondria in aged rat adrenal cortical cells were discussed.