title: Induction of germ-cell alkaline phosphatase by butyrate and cyclic AMP in BeWo choriocarcinoma cells.
abstract: BeWo choriocarcinoma cells synthesize two alkaline phosphatase isoenzymes: germ-cell alkaline phosphatase and tissue-unspecific alkaline phosphatase. We have made use of the differential heat-stabilities of these two isoenzymes to study the induction of germ-cell alkaline phosphatase by sodium butyrate and cyclic AMP (cAMP). Sodium butyrate causes a large induction of germ-cell alkaline phosphatase activity (approx. 35-fold after 96 h) after an initial lag period of 12-24 h. We showed that butyrate increases germ-cell alkaline phosphatase mRNA. Dibutyryl cAMP also induces germ cell alkaline phosphatase (approx. 2.5-fold after 96 h). When optimal concentrations of butyrate and dibutyryl cAMP were added simultaneously to cells, they caused a synergistic induction of activity. This suggested that these compounds use separate mechanisms to induce germ-cell alkaline phosphatase activity and that it is the cAMP moiety of dibutyryl cAMP that induces enzyme activity. This was confirmed by the use of two additional cAMP analogues, 8-(4-chlorophenylthio) cAMP and 8-bromo cAMP, and of two compounds, 3-methyl-1-isobutylxanthine and cholera toxin, which raise the endogenous concentration of cAMP. All four compounds caused a 2-fold increase in enzyme activity. Treatment of cells with 8-(4-chlorophenylthio) cAMP, 8-bromo cAMP and cholera toxin increased germ-cell alkaline phosphatase mRNA between 2- and 7-fold. These data suggest that this alkaline phosphatase isoenzyme is regulated at the level of its mRNA by cAMP, in a manner distinct from that of butyrate.
authors.affiliation: Department of Biochemistry, University of Liverpool, U.K.
authors.forename: J F
authors.initials: JF
authors.lastname: Telfer
authors.forename: C D
authors.initials: CD
authors.lastname: Green
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000096:biosynthesis*; D003994:Bucladesine / Q000494:pharmacology*; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D002822:Choriocarcinoma; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology*; D004790:Enzyme Induction; D005260:Female; D005854:Germ Cells / Q000201:enzymology; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D007700:Kinetics; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis; D013873:Thionucleotides / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D013873:Thionucleotides; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D003994:Bucladesine; D002772:Cholera Toxin; D000242:Cyclic AMP; D000469:Alkaline Phosphatase; D015056:1-Methyl-3-isobutylxanthine