Scanning Electron Microscopic Study on Mitochondrial Cristae in the Rat Adrenal Cortex

The three-dimensional structure of mitochondrial cristae In the rat adrenal cortex was studied by the osmium-DMSO-osmium method and scanning electron microscopy. Mitochondrial cristae of different zones were remarkably different. In the zona glomerulosa, intermedia and retlcularis the cristae were all tubulosaccular, although the degree of constriction varied somewhat from zone to zone. Several types were present in the zona fasdculata, Including lamellar, tubular and vesicular cristae. The vesicular cristae joined together to form a rosary-like structure with a continuous internal cavity. This structure seemed to be derived from tubular crlstae with strong constrictions at equal intervals. In the zona fasciculata some vesicular cristae also budded directly from the edge of lamellar cristae.