Alpha 1-adrenergic stimulation of iodide organification in mouse thyroid--inhibition by protein kinase C inhibitors.
Using mouse thyroid lobes incubated in vitro, a study was made of the subtype of alpha-adrenoceptors involved in iodide organification, induced by norepinephrine, and the possible role of protein kinase C in mediating the effect of norepinephrine. Norepinephrine and phenylephrine, alpha 1-agonists, increased the iodide organification in mouse thyroid lobes; however, clonidine, and alpha 2-agonist, showed a marginal effect. Prazosin, an alpha 1-blocker, but not yohimbine, an alpha 2-blocker, inhibited the norepinephrine-induced iodide organification. These results suggest the involvement of alpha 1-adrenoceptors. The stimulation of the iodide organification, induced by norepinephrine, was inhibited by omission of calcium from the medium and by protein kinase C inhibitors such as H 7, quercetin and trifluoperazine, but not by W-7, a calmodulin antagonist. Since tetradecanoylphorbol acetate, a stimulator of protein kinase C, mimicked the effect of norepinephrine in increasing iodide organification, extracellular calcium ion and protein kinase C would appear essential to the alpha 1-adrenergically regulated iodide organification in mouse thyroid.
Muraki
T
T
Department of Pharmacology, Tokyo Women's Medical College, Japan.
Tsukahara
F
F
Fujii
E
E
Nomoto
T
T
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006847:Hydrocarbons, Iodinated / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013961:Thyroid Gland / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*
D000316:Adrenergic alpha-Agonists; D006847:Hydrocarbons, Iodinated; D011493:Protein Kinase C; D002118:Calcium; D009638:Norepinephrine