Recombinant thyrotropin stimulates cAMP formation in CHO-K1 cells expressing recombinant chorionic gonadotropin receptor.
Using CHO-K1 cells expressing rat thyrotropin-receptor (CHO-rTSH-R cells) or rat chorionic gonadotropin-receptor (CHO-rCG-R cells), we have examined their reactivity or cross-reactivity to recombinant human thyrotropin (TSH) or human chorionic gonadotropin (hCG). TSH stimulated cAMP formation in CHO-rTSH-R cells dose-dependently, and the maximum response was obtained at 1 mIU/ml. hCG also increased cAMP in the cells from 10(4) mIU/ml, and the maximum stimulation was observed at 10(6) mIU/ml. 10(7) mIU of hCG had the same potency with 1 mIU of TSH to rTSH-R. On the other hand, 10(-1) mIU/ml of hCG increased cAMP content in CHO-rCG-R cells and reached the maximum level at 10(2) mIU/ml. TSH also showed the stimulatory activity to CHO-rCG-R cells. It increased cAMP formation in CHO-rCG-R cells dose-dependently from 10 mIU/ml to 10(3) mIU/ml. Thirty mIU of TSH was calculated to be equivalent to 1 mIU of hCG to CG-R. These results indicate that TSH and hCG cross-react each other with rTSH-R or rCG-R.
Gunji
K
K
Third Department of Internal Medicine, University of Yamanashi Medical School, Japan.
Endo
T
T
Ohno
M
M
Minegishi
T
T
Onaya
T
T
D000818:Animals; D016466:CHO Cells; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D002999:Clone Cells; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D051381:Rats; D011974:Receptors, LH / Q000096:biosynthesis* / Q000378:metabolism; D011989:Receptors, Thyrotropin / Q000096:biosynthesis* / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology; D013972:Thyrotropin / Q000494:pharmacology*; D014162:Transfection
D006063:Chorionic Gonadotropin; D011974:Receptors, LH; D011989:Receptors, Thyrotropin; D011994:Recombinant Proteins; D013972:Thyrotropin; D000242:Cyclic AMP