ULTRASTRUCTURAL DYNAMICS OF MITOCHONDRIAL MORPHOLOGY IN VARYING FUNCTIONAL FORMS OF HUMAN ADRENAL-CORTICAL ADENOMA

Adrenal cortical mitochondria display an extensive capacity to adapt m orphologically to the functional state of the adrenal cortical cell. I n the present study, we have used transmission electron microscopy to analyze cortical tissues from 3 normal human adrenal glands (zona fasc iculata and zona glomerulosa), and from 8 steroid-secreting adrenal co rtical adenomas (3 cortisol-producing, 4 aldosterone-producing, and 1 progesterone-producing tumor), correlating both clinical and biochemic al features with cellular ultrastructure. The morphology of mitochondr ia was related to the enzyme activity and steroid-biosynthetic capacit y of each tumor, Cells from aldosterone-producing adenomas demonstrate d a large number of elongated tubular mitochondria with characteristic bridging of inner membranes, producing a lamellar-type pattern, Cells from cortisol-producing adenomas showed large round mitochondria with vesicular or tubulovesicular inner membranes surrounded by a characte ristic dilated smooth endoplasmic reticulum, A highly unusual progeste rone-producing adenoma, in which a deficiency of 21 alpha-hydroxylase activity was demonstrated, showed a peculiar type of enlarged lamellar mitochondria with bright inner matrix and a reduced number of inner m embranes. Therefore, the ultrastructural characteristics of adrenal co rtical mitochondria appear to be potential markers for the differentia tion of steroid-producing adenomas, These studies point to the possibi lity of a broader use of electron microscopy in the study of adrenal t umors.