Stimulation by N6,O2′-Dibutyryl Cyclic Adenosine 3′:5′-Monophosphate of Ectopic Production of the Free β Subunit of Chorionic Gonadotropin by a Human Brain Tumor Cell Line

Previous studies have favored a basic difference in the regulation of specialized protein production by cells derived from the usual tissue of origin (eutopic) and cancer cells derived from a tissue not normally producing the protein (ectopic). Thus N 6, O 2′-dibutyryl cyclic adenosine 3′:5′-monophosphate was believed to stimulate only eutopic (but not ectopic) chorionic gonadotropin production, and butyrate to stimulate only ectopic (but not eutopic). However, in CBT, a human brain tumor cell line, we find that N 6, O2′ -dibutyryl cyclic adenosine 3′:5′-monophosphate, but not butyrate, stimulated ectopic production of the β subunit of chorionic gonadotropin. We conclude that neither butyrate nor cyclic adenosine 3′:5′-monophosphate derivatives reliably discriminate ectopic from eutopic regulation.