Preparation of adrenocortical cell suspension highly responsive to ACTH or dibutyryl-cyclic AMP. Effects of albumin, Ca2+ or stress.

Although the cells of the adrenal cortex can synthesize cholesterol from acetate [l] most of the cholesterol used for synthesis of corticosteroid hormones derives from plasma [2-41. Free and esterified cholesterol enter the adrenal cell in a form of a lipoprotein [S] either of high [6-81 or low density [9,10]. Chronic administration of corticotropin (ACTH) has been shown to stimulate not only the entry of plasma cholesterol into the adrenal cells, but also its utilization for steroid hormone synthesis [S ,6,8 91, as well as the hydrolysis of cholesterol esters [ 11,121. Initial studies on lipoprotein cholesterol uptake by the adrenal cortex were made in quartered glands [6] and in isolated cells in culture, either from normal adrenal [89], or adrenal tumor [S-lo]. A better approximation to in vivo conditions seems to be the investigation of cholesterol uptake, and its utilization for steroid hormone synthesis, by freshly isolated cells. These however require a preparation containing only cells of zona fasciculata-reticularis, undamaged and highly responsive to ACTH or dibutyryl-cyclic AMP, devoid of erythrocytes and/or other types of cells. Here we have attempted to prepare such a suspension.