Epidermal growth factor and phorbol ester actions on the TSH induced down regulation of the isoenzyme I (PKA I) of cyclic AMP-dependent protein kinases in dog thyroid cell primary cultures.
In dog thyroid cell primary cultures the prolonged presence (up to 4-6 days) of TSH induced down regulation of the isoenzyme I (PKA I) of cAMP-dependent protein kinases. In the simultaneous presence of TSH and EGF this down regulation of PKA I was maintained, although it was slightly smaller than in assays without EGF. In contrast, the simultaneous presence of TPA, totally inhibited the TSH induced down regulation of PKA I. These results partly explain the previously observed additivity of TSH and EGF, and the non-additivity of TSH and TPA actions on cell proliferation in these cells.
Roger
P P
PP
Institut de Recherche Interdisciplinaire, Université Libre de Bruxelles, Belgium.
Breton
M F
MF
Dumont
J E
JE
Pavlovic-Hournac
M
M
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D003600:Cytosol / Q000737:chemistry; D004285:Dogs; D015536:Down-Regulation / Q000187:drug effects; D004357:Drug Synergism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism*; D010703:Phorbol Esters / Q000494:pharmacology*; D011494:Protein Kinases / Q000378:metabolism*; D013961:Thyroid Gland / Q000187:drug effects* / Q000201:enzymology; D013972:Thyrotropin / Q000494:pharmacology
D007527:Isoenzymes; D010703:Phorbol Esters; D005576:Colforsin; D004815:Epidermal Growth Factor; D013972:Thyrotropin; D011494:Protein Kinases