The ultrastructure of the human adrenal cortex before and after stimulation with ACTH

Steroid production and membrane potential measurement in cells of the adrenal cortex

1. The relation between corticosteroid production and the cellular membrane potential of adrenocortical cells has been investigated using a flow system for the incubation in vitro of adrenal glands from neonatal rabbits. Corticosteroid production by the adrenal cells was determined by a fluorescence method; membrane potentials were measured with glass micro-electrodes.2. Adrenocorticotrophic hormone (ACTH) increased corticosteroid production without altering the membrane potential of the adrenocortical cells. Conversely, a 5-fold increase in [K](o) did not increase corticosteroid production but decreased the cellular membrane potential. The increase in [K](o) did not impair the stimulation of corticosteroid production by ACTH.3. The log dose-response relation between the concentration of ACTH in the incubation medium and the amount of corticosteroid produced by the adrenal tissue was linear.4. No evidence was found of a direct relation between the production of corticosteroid by adrenocortical cells and the cellular membrane potential. Indeed, the output of steroid appeared to be relatively independent of the polarization of the cell membrane.

Ultrastructural morphometry of normal adrenal cortex and of hyperplastic adrenals in gushing's disease

Surgical specimens of 4 normal adrenal glands and of 5 hyperplastic ones in Cushing's disease were studied ultrastructurally. The ultrastructure of the three zones of each adrenal gland was morphometrically and statistically analyzed. Comparing the statistical data of the three zones of the normal gland, the development of smooth endoplasmic reticuium and rough endoplasmic reticuium showed an increase from the outer zona glomerulosa to the inner zona fasciculata and reticularis. Also, the mitochondria were more numerous in the inner zona reticularis than in the outer zones. In Cushing's disease, the smooth endoplasmic reticuium, the rough endoplasmic reticuium, and the mitochondria were developed to a significantly higher degree than in normal human adrenal glands. The distribution of the cell organelles in the zona fasciculata and zona reticularis is almost alike in normal adrenal glands and in the adrenal cortex in Cushing's disease, except that the smooth endoplasmic reticuium in the zona reticularis was less extensive than in the zona fasciculata. The volume percentages of lipid vacuoies in the hyperplastic zona fasciculata in Cushing's disease was strongly and significantly decreased in comparison to normal adrenal glands. Our ultrastructural findings and the statistical data were in accordance with the results from animal experiments with adrenocorticotropic hormone (ACTH) stimulation and confirmed former qualitative ultrastructural findings concerning human adrenal gland changes in ACTH-dependent Cushing's disease.

The adrenal cortex in ectopic adrenocorticotropic hormone syndrome: A morphological study with histology, transmission and scanning electron microscopy, flow cytometry, and image analysis

The surgically removed adrenal glands of an 83-year-old woman with ectopic adrenocorticotropic hormone syndrome were studied by light microscopy, transmission and scanning electron microscopy, and flow-cytometric and image analyses for DNA ploidy. Light microscopy revealed marked adrenocortical hyperplasia. The majority of the large fasciculata cells were lipid-depleted compact cells, some with large nuclei. By transmission electron microscopy, marked abundance of smooth endoplasmic reticulum was noted. Mitochondria were large, had vesicular or tubulovesicular cristae, and showed focal cavitation in their internal compartments. Lysosomes were numerous in many large cells. Long microvilli were prominent on the cell surfaces and interdigitating with adjacent cells. Scanning electron microscopy disclosed many conspicuous microvilli and small pits on the cell membranes. The microvillous hyperplasia is most likely destined to facilitate uptake of hormone precursors or discharge of synthesized hormones by increasing the cell surface area; the small pits on cell membranes may reflect endocytosis of hormone precursors required for accelerated corticosteroid synthesis. Flow-cytometric and image analysis of the adrenocortical cells showed aneuploid and polyploid DNA populations, providing evidence that aneuploidy and polyploidy may occur not only in neoplastic but also in hyperplastic cells.

Human normal and neoplastic adrenocortical cells in tissue culture observed by scanning electron microscopy

Human normal and neoplastic adrenocortical cells were incubated under stimulation with ACTH and observed by scanning electron microscopy. Cultured normal adrenocortical cells gathered into small clusters, each cell of which had a polarity or orientation evidenced by two different aspects. In one aspect, the cell surface rounded up and microvilli protruded vertically. Pits were found among or close to the groups of microvilli. In the other aspect, the cell surface was flattened and well-developed microvilli ran horizontally. These two aspects of the cultured cells were thought to correspond to the cell surface facing the intercellular space and that facing the perisinusoidal space, respectively. In incubated cell clusters of adrenocortical adenomas with Conn's syndrome, most cells lost this polarity or orientation and unstimulated cells existed as unit of the clusters, but all adenoma cells reacted to ACTH in the same manner. Microvilli were distributed unevenly. Filopodia were noticed in some cells. Bleb-like structures appeared frequently and some of them were about to be extricated from the cell surface as in normal adrenocortical cells. Adrenocortical adenomas with Cushing's syndrome showed remarkable responses to ACTH. Their cell surface was unclean with the adherence of fragmented cytoplasm and bleb-like structures. Horizontally running elongated microvilli were almost indistinguishable from collagen fibrils. Moreover, collagen fibrils were entangled with microvilli.

Androgen producing adrenocortical carcinoma

Two cases of androgen secreting adrenocortical carcinoma have been described by light and electron microscopy. The histological and ultrastructural features of the tumour cells were similar to those of compact cells of zona reticularis and to those described in virilizing adenomas. They possess numerous mitochondria with lamellar and tubular cristae, abundant smooth endoplasmic reticulum, lipofuscin bodies and scanty lipid. Irregularly shaped, crenated mitochondria, with outpouchings of the outer limiting membrane have also been observed. The clusters of neoplastic cells were surrounded by basement membrane which demonstrated a focal discontinuity, probably reflecting malignancy of the tumours. Hyperplasia of smooth endoplasmic reticulum and the presence of outpouchings of the mitochondrial outer limiting membrane might be the morphological manifestation of endocrine activity of the tumours.

Ultrastructural changes of the adrenal cortex in Cushing's syndrome treated with aminoglutethimide (Elipten Ciba)

The main ultrastructural feature of human adrenal cortices following administration of aminoglutethimide (Elipten CIBA), a steroid biosynthesis blocking agent, is a striking intracellular accumulation of lipids, also seen in the light microscopy. The lipids accumulate in the adrenocortical cells but are also stored in the cytoplasm of pericapillary histiocytes. The lipids are present in the adrenocortical cells mostly as rounded liposomes of variable size, whereas those in the histiocytes usually show up as an amorphous debris with abundant myelin figures and cholesterol crystals. In some areas of the adrenal cortex activated histiocytes changing into lipophages may become the prevalent cell. They also take the place of destroyed adrenocortical cells and can form compact cell aggregates of variable size or even columnar strands between neighbouring capillaries, thus resembling columns of adrenocortical cells. In some of the adrenocortical cells focal cytoplasmic degradation, turning into coagulation necrosis, was observed. In others initial cytolysis was found. In contrast with earlier findings in experimental animals, mitochondrial changes in humans were not a prominent feature. The only changes occasionally observed were a focal disappearance of the vesicular cristae and a concomitant fibrillary loosening of the mitochondrial matrix.

A new crystal-containing cell in human adrenal cortex

Electron microscope examination of the adrenal cortex from three male human subjects revealed a special type of cell occurring in periendothelial spaces, in all adrenal cortex zones. It is a clear, spindle-shaped cell the principal cytoplasmic features of which are crystalline inclusions with a structure similar to that of the Reinke crystals of human testicular interstitial cells and an abundance of microfilaments. Enzymatic digestions with pronase, pepsin, and ribonuclease were performed, and no digestion of the crystals was obtained. The crystals had no peroxidase or acid phosphatase activities. This cell appears to be exclusive to human males and it may be related to adrenal androgen secretion.

Adrenal cholesterol: localization by electron-microscope autoradiography

As determined by electron-microscope autoradiography of adrenal glands containing tritiated cholesterol and by modified differential centrifugation techniques, 70 to 80 percent of adrenal cholesterol is contained within lipid droplets of rat adrenal cortical cells.