title: Antagonism by dibutyryl adenosine cyclic 3',5'-monophosphate and testololactone of concanavalin A capping.
abstract: Exposure of CHO-K1 cells in vitro to dibutyryl adenosine cyclic 3',5'-monophosphate (DBcAMP) plus testololactone produces a rapid, reversible antagonism of ligand-induced collection of initially dispersed concanavalin A (Con A) binding sites into a caplike mass. Morphologically, as Con A capping occurs, the cells become less spread and then round completely. With prolonged Con A exposure, cells cultured in either the absence or the presence of DBcAMP plus testololactone cap and round. Capping is blocked by cold treatment and respiratory inhibitors. Colcemid at concentrations greater than 1 muM promotes both Con A capping and cell rounding. Cytochalasin B at similar concentrations inhibits both capping and cell rounding. Treatment of cells with Con A has little effect on intracellular cAMP concentration. Possible mechanisms by which cAMP may modulate the movement of Con A binding sites are discussed.
mesh_terms: D000818:Animals; D001386:Azides / Q000494:pharmacology; D001666:Binding Sites, Antibody; D003994:Bucladesine / Q000494:pharmacology*; D002460:Cell Line; D003078:Colchicine / Q000494:pharmacology; D003080:Cold Temperature; D003208:Concanavalin A / Q000378:metabolism*; D006224:Cricetinae; D003571:Cytochalasin B / Q000494:pharmacology; D004336:Drug Antagonism; D005260:Female; D005452:Fluoresceins; D007461:Iodoacetates / Q000494:pharmacology; D008854:Microscopy, Electron; D010053:Ovary; D013738:Testolactone / Q000494:pharmacology*; D013806:Theophylline / Q000494:pharmacology
chemical_list: D001386:Azides; D005452:Fluoresceins; D007461:Iodoacetates; D003208:Concanavalin A; D003571:Cytochalasin B; D003994:Bucladesine; D013738:Testolactone; D013806:Theophylline; D003078:Colchicine