Transmission and scanning electron microscopic observations of mouse adrenocortical adenoma cells (Y-1) in non-stimulated and stimulated states.

ACTH sensitive murine adrenocortical adenoma cells (Y-1) were examined by transmission and scanning electron microscopes under non-stimulated and stimulated conditions. They showed the ultrastructural characteristics which were fairly different from those of the original adrenocortical cells of LAF1 mice. The smooth-surfaced endoplasmic reticulum (sER) were poorly developed, and the mitochondrial cristae showed lamellar rather than tubular or tubulo-vesicular type. Administration of ACTH induced rounding-up of the Y-1 cells with slight increase in sER, BUt no mitochondria with vesicular inner structure appeared. The effects of dbcAMP on the morphology of the Y-1 cells were similar to those of ACTH except that the rounding-up occurred more rapidly and uniformly.