title: Retinoic acid-induced changes in epidermal growth factor binding and in biological responses mediated by phorbol ester tumor promoter.
abstract: We investigated the ability of retinoic acid (RA) to alter the binding of epidermal growth factor (EGF) to Rat-1 and Swiss mouse 3T3 cells, the EGF-related induction of ornithine decarboxylase (ODC) activity and DNA synthesis. Pretreatment of 3T3 cells with 10(-10)--10(-5) M RA produced a dose-dependent increase in EGF binding. The increased EGF binding appeared to result from an increased number of EGF receptors and did not occur in Rat-1 cells which, unlike 3T3 cells, possessed measureable amounts of cellular retinoic acid binding protein (CRABP). Both cell lines responded to RA pretreatment with an increase in EGF- and TPA-induced ODC activity, without a concomitant increase in DNA synthesis in either cell line. We suggest that the increase in EGF binding induced by RA in 3T3 cells is apparently unrelated to alterations in EGF-induced biological responses and to the presence of CRABP.
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D051379:Mice; D009955:Ornithine Decarboxylase / Q000378:metabolism; D010704:Phorbols / Q000494:pharmacology*; D051381:Rats; D018168:Receptors, Retinoic Acid; D013696:Temperature; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D002352:Carrier Proteins; D010704:Phorbols; D018168:Receptors, Retinoic Acid; D014212:Tretinoin; D004815:Epidermal Growth Factor; D004247:DNA; D009955:Ornithine Decarboxylase; D013755:Tetradecanoylphorbol Acetate