title: Thyrotrophin and prostaglandin E2 increase calmodulin levels and cyclic AMP phosphodiesterase activity in cultured porcine thyroid cells.
abstract: Thyrotrophin (TSH) and prostaglandin E2 (PGE2) increased cellular cyclic AMP (cAMP), calmodulin levels and cAMP phosphodiesterase activity in cultured porcine thyroid cells. Dibutyryl cAMP (dbcAMP), a stable analogue of cAMP, increased calmodulin levels and cAMP phosphodiesterase activity. These results indicate that TSH- and PGE2-stimulated increases in calmodulin are mediated by cAMP. This increased concentration of calmodulin in turn stimulates cAMP phosphodiesterase. Double reciprocal plots of cAMP hydrolysis yielded two apparent Michaelis constants (Km); the lower in the 1 mumol/l and the higher in the 10 mumol/l range. Thyrotrophin, PGE2 and dbcAMP increased the values of maximal velocity without changing the Km values.
authors.affiliation: Department of Gerontology, Endocrinology and Metabolism, School of Medicine, Shinshu University, Nagano-ken, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Takasu
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002147:Calmodulin / Q000378:metabolism*; D002478:Cells, Cultured; D015232:Dinoprostone; D011458:Prostaglandins E / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013552:Swine; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D002147:Calmodulin; D011458:Prostaglandins E; D003994:Bucladesine; D013972:Thyrotropin; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D015232:Dinoprostone