title: Hormone receptors and cyclic nucleotide metabolism in cancer cells.
abstract: The possibility of a relationship between cyclic AMP formation and metabolic processes in tumours has been investigated. Changes in basal activity and hormone-responsiveness of adenylate cyclase were demonstrated in plasma membranes and intact cells from pre-cancerous liver of rats fed a diet containing the carcinogen 3'-methyl-4-dimethylaminoazobenzene. Basal adenylate cyclase activity in hyperplastic parathyroid gland membranes was 200% higher than that in parathyroid adenoma membranes, corresponding with their relative rates of parathyroid hormone secretion in vitro. Membrane adenylate cyclase activity in hypernephromas was consistently 100--300% higher than in adjacent human renal cortex. Furthermore the adenylate cyclase activity of the tumour membranes was not influenced by a wide range of hormones which were effective stimulants in 'normal' renal cortex membranes. Conversion of 25-hydroxycholecalciferol to 1,25-dihydrocholecalciferol could not be demonstrated in either hypernephroma or adjacent renal cortical tissue. However, three of the four hypernephromas tested secreted a bone-resorbing factor. Cyclic AMP formation was increased by salmon, human and porcine calcitonins in both plasma membranes and intact cells from a poorly differentiated epidermoid cell carcinoma which was itself secreting calcitonin in culture. This phenomenon might be related to a feedback regulation of calcitonin production in this cell line. The observations are consistent with the concept of a relationship between cyclic AMP formation and certain metabolic functions (e.g. hormone production) in tumour cells.
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000378:metabolism; D000236:Adenoma / Q000201:enzymology / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002116:Calcitonin / Q000494:pharmacology; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D006887:Hydroxycholecalciferols / Q000378:metabolism; D007672:Kidney Cortex / Q000201:enzymology / Q000378:metabolism; D007680:Kidney Neoplasms / Q000201:enzymology / Q000378:metabolism; D008113:Liver Neoplasms / Q000139:chemically induced / Q000201:enzymology / Q000378:metabolism; D008749:Methyldimethylaminoazobenzene / Q000494:pharmacology; D009369:Neoplasms / Q000378:metabolism*; D009712:Nucleotides, Cyclic / Q000378:metabolism*; D010280:Parathyroid Glands / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D010282:Parathyroid Neoplasms / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D006887:Hydroxycholecalciferols; D009712:Nucleotides, Cyclic; D011956:Receptors, Cell Surface; D008749:Methyldimethylaminoazobenzene; D002116:Calcitonin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases