Cellular structure and function of mouse adrenocortical tumor cells Y-1 in the post-treatment state of low Ca2+

Under lowered Ca2+ content and in the post-treatment state of low Ca2+, we studied the cellular structure and functioning in mouse adrenocortical tumor cells, Y-1. These cells had been maintained in Ham F12 medium containing 10% fetal calf serum. The Ca2+ present in this complete medium was 0.39 mM. Under a slightly lowered Ca2+ (0.29 mM) produced by EGTA, the cells had many blebs on their surfaces and specific functional activity decreased in steroidogenesis as did ACTH reactivity. In the post-treatment state of a low Ca2+, the cellular surface was covered with many short microvilli and there was greater cellular activity than in the control cells. When the Ca2+ concentration was below 0.17 mM, the cellular structure and functioning were disturbed, and there was no recovery even at the physiological Ca2+ after the removal of EGTA.