Zonation of the adrenal cortex. I. Isolation of mitochondria from the zona glomerulosa of the bovine adrenal cortex.

Isolation procedures for mitochondria from the zona glomerulosa of the bovine adrenal cortex are described in comparison to those isolated from the zona fasciculo-reticularis. The cristal membranes of mitochondria in the zona glomerulosa in situ are tubular or tubulo-vesicular, whereas those of mitochondria in the zona fasciculo-reticularis in situ are vesicular. When mitochondria are isolated from the former zone, they invariably showed a condensed configuration regardless of isolation media, whereas those isolated from the later zone in a ST medium showed an orthodox configuration. When Ca2+ was added to mitochondria isolated form either zone in an STE medium in the condensed configuration, transition from the condensed to the orthodox configuration took place; the cristel membrane of mitochondria from the zona glomerulosa became tubular or tubulo-vesicular and those of mitochondria from the zona fasciculo-reticularis became vesicular. Purity of mitochondria thus obtained from the zona glomerulosa was examined by electron microscope and marker enzymes. Coupling efficiency of mitochondria was found to be remarkably affected by temperature during the isolation procedures and a choice of substrates.