Non-functioning adrenocortical adenoma in culture. Quantitative and morphological observations.

This report describes the morphological responses of unstimulated and stimulated non-functioning adrenocortical adenoma in culture. The removed adrenocortical adenoma was composed mainly of clear-type cells and partially had a small area of cholesterol granuloma. These adenoma cells had many lipid droplets and round to long rod-shaped mitochondria with tubular or tubulo-lamellar cristae which were similar to those in Cushing's adenoma. The non-functioning adrenocortical adenoma cells which were incubated in vitro under ACTH (10 mIU/ml) and angiotensin II (10(-6) M/ml) stimulation, were examined by phase contrast microscopy, transmission and scanning electron microscopy, and the content of cortisol and aldosterone in the culture medium was measured by radioimmunoassay. As a result of exposure of ACTH, the cultured cells revealed the retraction response and production of cortisol and aldosterone. After administration of ACTH for many days, the cultured cells showed characteristic changes in sER and mitochondria. The sER were markedly developed and packed tightly into a network of dilated tubules. Mitochondria were larger and more numerous than in the unstimulated cells. The mitochondria appeared to be entwined by the tubules of the sER. Lipid droplets decreased in number.