Gap junctions and ACTH sensitivity in Y‐1 adrenal tumor cells

Initial studies of adrenocorticotropin-sensitive (ACTH-sensitive) and ACTH-insensitive Y-1 adrenal cortical tumor cell lines suggest a relationship between responsiveness to ACTH and the presence of gap junctions. An ACTH-sensitive clone of Y-1 cells possesses gap junctions and these junctions appear to enlarge with ACTH treatment. Gap junctions have not been observed, however, in an ACTH-insensitive clone of Y-1 tumor cells even when stimulated to produce cyclic adenosine monophosphate and steroids with cholera toxin.