title: GH3 cells expressing constitutively active Gs alpha (Q227L) show enhanced hormone secretion and proliferation.
abstract: cAMP levels in GH3gsp cells (Q227L mutation of Gs alpha), in comparison with uninfected GH3 and GH3vt (with vector alone) cells, were two to three fold (P< 0.01) higher (basal), and 10-20 fold (P<0.001) higher (in the presence of isobutyl methylxanthine, (IBMX)). Proliferation of GH3gsp cells after 7 days in culture, as determined by cell number and [(3)H]thymidine incorporation, were up to 25% (respectively P <0.001 and P < 0.02) higher. After chronic (4 days) but not acute (15 min) exposure to forskolin (10 microM) or dibutyryl cAMP (50 microM) all cell types showed a greater than 200% (P < 0.001) increase in [(3)H]thymidine incorporation. Secretion of prolactin and growth hormone by GH3gsp cells were two to four fold (P <0.001) higher than GH3 and GH3vt cells after 4 h and 10-12 fold (P <0.001) higher after 8 h. In conclusion GH3 cells possessing Q227L have a higher proliferation rate and secrete higher levels of prolactin and growth hormone which are associated with higher levels of cAMP.
authors.affiliation: Department of Medicine, University of Wales College of Medicine, Cardiff, UK. Jack Ham@CF.AC.UK
authors.forename: J
authors.initials: J
authors.lastname: Ham
authors.forename: M
authors.initials: M
authors.lastname: Ivan
authors.forename: D
authors.initials: D
authors.lastname: Wynford-Thomas
authors.forename: M F
authors.initials: MF
authors.lastname: Scanlon
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015153:Blotting, Western; D003994:Bucladesine / Q000494:pharmacology; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000235:genetics*; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D009154:Mutation / Q000502:physiology*; D011388:Prolactin / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000502:physiology
chemical_list: D005576:Colforsin; D003994:Bucladesine; D011388:Prolactin; D013006:Growth Hormone; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D015056:1-Methyl-3-isobutylxanthine; D013936:Thymidine