title: Phorbol esters stimulate the transport of anionic amino acids in cultured human fibroblasts.
abstract: The effect of phorbol esters on the transport of amino acids has been evaluated in cultured human fibroblasts. The activity of the Na(+)-dependent system XAG- for anionic amino acids is selectively and markedly stimulated by phorbol esters. The effect is maximal within 15 min; it is attributable to an increase in transport maximum (Vmax) and not prevented by inhibitors of protein synthesis. The half-maximal stimulation is observed at concentrations of phorbol 12,13-dibutyrate lower than 100 nM. Prolonged incubations in the presence of 1 microM phorbol 12,13-dibutyrate lower the binding of the ligand to its receptor with a loss of the stimulatory effect on transport. The results presented indicate that the stimulation of amino acid transport through system XAG- by phorbol esters requires the activation of protein kinase C.
authors: Istituto di Patologia Generale, Università di Parma, Italy.
authors: R
authors: R
authors: Franchi-Gazzola
authors: O
authors: O
authors: Bussolati
authors: R
authors: R
authors: Visigalli
authors: B M
authors: BM
authors: Rotoli
authors: P A
authors: PA
authors: Rossi
authors: G G
authors: GG
authors: Guidotti
authors: G C
authors: GC
authors: Gazzola
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001692:Biological Transport; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D015240:Phorbol 12,13-Dibutyrate / Q000008:administration & dosage / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C