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Title: Phorbol esters modulate cyclic AMP accumulation in porcine thyroid cells

In cultured porcine thyroid cells, during 60 min incubation phorbol 12-myristate 13-acetate (PMA) had no effect on basal cyclic AMP accumulation and slightly stimulated cyclic AMP accumulation evoked by thyroid stimulating hormone (TSH) or forskolin. Cholera toxin-induced cyclic AMP accumulation was significantly stimulated by PMA. On the other hand, cyclic AMP accumulation evoked by prostaglandin E/sub 1/ or E/sub 2/ (PGE/sub 1/ and PGE/sub 2/) was markedly depressed by simultaneous addition of PMA. These opposing effects of PMA on cyclic AMP accumulation evoked by PGE and cholera toxin were observed in a dose-related fashion, with half-maximal effect of around 10/sup -9/ M in either case. The almost same effects of PMA on cyclic AMP accumulation in basal and stimulated conditions were also observed in freshly prepared thyroid cells. The present study was performed in the presence of phosphodiesterase inhibitor, 3-iso-butyl-1-methylxanthine (IBMX), indicating that PMA affected adenylate cyclase activity. Therefore, it is suggested that PMA may modulate the production of cyclic AMP in response to different stimuli, possibly by affecting several sites in the adenylate cyclase complex in thyroid cells.
Authors:
; ; ;
Publication Date:
OSTI Identifier:
7252535
Resource Type:
Journal Article
Resource Relation:
Journal Name: Life Sci.; (United States); Journal Volume: 42:22
Research Org:
Dokkyo Univ. School of Medicine, Tochigi (Japan)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; AMP; BIOLOGICAL ACCUMULATION; CYCLASES; ENZYME ACTIVITY; PHORBOL ESTERS; BIOLOGICAL EFFECTS; DOSE-RESPONSE RELATIONSHIPS; ENZYME INHIBITORS; PROSTAGLANDINS; SWINE; THYROID CELLS; TOXINS; TSH; ANIMAL CELLS; ANIMALS; ANTIGENS; CARCINOGENS; DOMESTIC ANIMALS; ENZYMES; ESTERS; HORMONES; LYASES; MAMMALS; MATERIALS; NUCLEOTIDES; ORGANIC COMPOUNDS; PEPTIDE HORMONES; PITUITARY HORMONES; TOXIC MATERIALS; VERTEBRATES 560300* -- Chemicals Metabolism & Toxicology