Response to ACTH and dibutyryl cyclic AMP by enucleated adrenocortical tumor cells

Y-1-L cells, a subline of the Y-1 functional murine adrenocortical tumor cell line, were enucleated with cytochalasin B and the response of these enucleated cells to ACTH and dibutyryl cyclic AMP (dbcAMP) was examined. Enucleated Y-1-L cells maintained a basal steroid output for at least 24 h and responded to either ACTH (10 mU/ml) or dbcAMP (1 mM) by a change from flat to rounded cell shape, and by increased steroidogenesis. The steroidogenic response of enucleated cells during the first 3 h after enucleation was highly significant and, though it decreased rapidly thereafter, it persisted to a limited degree for up to 12 h. On the other hand, the morphologic change could be induced even at 33 h after enucleation. The results of this study show that the nucleus is not required for the expression of the acute effects of ACTH or dbcAMP and that the cytoplasmic components necessary for cell 'rounding' and a steroidogenic response are stable for 36 h and 12 h, respectively.