The TSH-dependent potassium channel in a cloned rat thyroid cell line.
We found a TSH-dependent K+ channel in the membrane of a rat thyroid cell line (FRTL-5 cell). This K+ channel is activated by extracellular application of the thyroid stimulating hormone (TSH). Treatment of dibutyryladenosine cyclic monophosphate (Bt2 cAMP) also activated the TSH-dependent K+ channel. Intracellular application of protein kinase A activates this K+ channel without the presence of free Ca2+. These findings indicate that the thyroid K+ channel is activated through the TSH-cAMP-protein kinase A system. This is the first report of a polypeptide hormone activated K+ channel and it should be useful for examining the effects of this K+ channel on thyroid cell functions.
First Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.
A
A
Yoshida
I
I
Hisatome
H
H
Kotake
S
S
Taniguchi
R
R
Sato
T
T
Kouchi
Y
Y
Ueta
Y
Y
Mitani
C
C
Shigemasa
H
H
Mashiba
D000595:Amino Acid Sequence; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002999:Clone Cells; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000187:drug effects*; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology*
D015221:Potassium Channels; D003994:Bucladesine; D013972:Thyrotropin; D011494:Protein Kinases; D002118:Calcium