Thyroid stimulating hormone and N6-2'-O-dibutyryladenosine 3'-5'-cyclic monophosphate decrease 110,000-130,000 M(r) tyrosine-phosphorylated substrate in rat thyroid cells.
By immunoblotting using monoclonal antibodies against phosphotyrosine, thyroid stimulating hormone (TSH)-induced changes in tyrosine phosphorylation of intracellular proteins in earlier passages of rat thyroid cells (FRTL-5) were studied. TSH and N6-2'-O-dibutyryladenosine 3'-5'-cyclic monophosphate (Bt2cAMP) decreased the phosphotyrosine content of 110,000-130,000 M(r) substrate (p120) in parallel with a morphological change in FRTL-5 cells. Insulin-like growth factor-I (IGF-I) or phorbol 12-myristate 13-acetate (PMA) only showed an attenuated reaction compared with that of TSH or Bt2cAMP. Further, sodium orthovanadate (a protein tyrosine phosphatase inhibitor) could not inhibit this reaction. These data suggest possible inhibitory effects of TSH and adenosine 3'-5'-cyclic monophosphate (cAMP) on tyrosine kinases that act on this substrate.
Takano
T
T
Department of Laboratory Medicine, Osaka University Medical School, Japan.
Sumizaki
H
H
Liu
G
G
Amino
N
N
D000818:Animals; D000911:Antibodies, Monoclonal; D003994:Bucladesine / Q000494:pharmacology*; D018929:Cell Culture Techniques; D002460:Cell Line; D015151:Immunoblotting; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008970:Molecular Weight; D015688:Oncogene Protein pp60(v-src) / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology*; D014638:Vanadates / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D019000:Phosphotyrosine; D014638:Vanadates; D003994:Bucladesine; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src); D013755:Tetradecanoylphorbol Acetate