title: Thyrotropin activates both the cyclic AMP and the PIP2 cascades in CHO cells expressing the human cDNA of TSH receptor.
abstract: The effect of thyrotropin (TSH) on cyclic AMP accumulation, phosphatidylinositol bisphosphate (PIP2) hydrolysis and [Ca2+]i rise has been studied in CHO cells stably transfected with human TSH receptor (hTSHR) cDNA. In human thyroid slices, TSH activates these two intracellular cascades with a higher affinity for the adenylate cyclase activation (from 0.1 to 1 mU/ml TSH) than for phospholipase C activation (from 1 to 10 mU/ml TSH). The CHO cells transfected with the recently cloned cDNA of human TSH receptor respond in the same way to TSH. They respond between 0.1 and 1 mU/ml TSH for cyclic AMP accumulation and between 1 and 10 mU/ml TSH for inositol monophosphate (IP1) increase. In these same cells, TSH 10 mU/ml, but not forskolin (10 microM), or dibutyryl cyclic AMP (100 microM), clearly enhances intracellular calcium concentration [( Ca2+]i). Our results demonstrate unequivocally that a single transcription unit has the potential to encode receptor molecules coupled to both cascades.
authors.affiliation: Institute of Interdisciplinary Research, University of Brussels, School of Medicine, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Van Sande
authors.forename: E
authors.initials: E
authors.lastname: Raspé
authors.forename: J
authors.initials: J
authors.lastname: Perret
authors.forename: C
authors.initials: C
authors.lastname: Lejeune
authors.forename: C
authors.initials: C
authors.lastname: Maenhaut
authors.forename: G
authors.initials: G
authors.lastname: Vassart
authors.forename: J E
authors.initials: JE
authors.lastname: Dumont
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism*; D011989:Receptors, Thyrotropin / Q000235:genetics*; D013972:Thyrotropin / Q000494:pharmacology*; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D007295:Inositol Phosphates; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D011989:Receptors, Thyrotropin; D005576:Colforsin; D003994:Bucladesine; D013972:Thyrotropin; D004247:DNA; D000242:Cyclic AMP; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D002118:Calcium