title: Cholinergic and alpha-adrenergic stimulation of prostaglandin release by dog thyroid in vitro.
abstract: Dog thyroid slices released in their incubation medium prostaglandins E2 (PGE2), F2 alpha (PGF2 alpha), 15-keto-13,14-dihydro-F2 alpha, and thromboxane B2 (TxB2), as measured by direct RIA. This release could be inhibited by indomethacin and naproxen, indicating that it corresponded to a neosynthesis. Carbamylcholine (2--100 microns) stimulated the release of PGE2, PGF2 alpha, and TxB2, whereas epinephrine (20 microns to 1 nM) enhanced the release of PGE2 and PGF2 alpha but had no effect on TxB2. These stimulations were inhibited by atropine and dihydroergocryptine, respectively, suggesting that a muscarinic and an alpha-adrenergic receptor were involved. The ionophore A23187 reproduced these stimulations, and the stimulatory effects of carbamylcholine and epinephrine were inhibited in the absence of exogenous Ca++ and after EGTA depletion. Ca++ thus appears as a major regulator of PG production in the thyroid. TSH (0.06--10 MU/ml) and dibutyryl cAMP had no effect on the release of PGE2, PGF2 alpha, or TxB2 by dog thyroid in vitro.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology*; D009288:Naproxen / Q000494:pharmacology*; D011453:Prostaglandins / Q000378:metabolism*; D011460:Prostaglandins F / Q000378:metabolism; D011863:Radioimmunoassay; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*
chemical_list: D011453:Prostaglandins; D011460:Prostaglandins F; D000001:Calcimycin; D009288:Naproxen; D001285:Atropine; D002217:Carbachol; D007213:Indomethacin; D004837:Epinephrine