Alpha 1-adrenergic regulation of thyrotropin-stimulated release of 3, 5, 3' -triiodothyronine and thyroxine from perifused mouse thyroid.
The effect of methoxamine, a specific alpha 1-adrenergic agonist, on the release of T3, T4 and cAMP from perifused mouse thyroid was studied to clarify the role of the alpha 1-adrenergic receptor in the regulation of thyroid hormone secretion. TSH-stimulated T3 and T4 release was inhibited significantly by methoxamine. With regard to cAMP release, methoxamine inhibited TSH-stimulated cAMP release in the presence of 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone but did not inhibit TSH-stimulated cAMP release in the presence of 3-isobutyl-1-methylxanthine. Methoxamine did significantly suppress TSH-stimulated release of T3 and T4 in the presence of each phosphodiesterase inhibitor. Depletion of Ca2+ in the perifusion buffer abolished completely the inhibitory effect of methoxamine on TSH-stimulated T3 and T4 release. The present study suggests that activation of the alpha 1-adrenergic receptor inhibits TSH-stimulated T3 and T4 secretion through a Ca(2+)-dependent mechanism in the mouse thyroid gland.
Oda
Y
Y
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Tajima
K
K
Mori-Tanaka
M
M
Matsui
I
I
Kitajima
K
K
Miyagawa
J
J
Hanafusa
T
T
Mashita
K
K
Tarui
S
S
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D051379:Mice; D011224:Prazosin / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D013961:Thyroid Gland / Q000378:metabolism*; D013972:Thyrotropin; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000378:metabolism*
D011942:Receptors, Adrenergic, alpha; D014284:Triiodothyronine; D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone; D013972:Thyrotropin; D000242:Cyclic AMP; D008729:Methoxamine; D013974:Thyroxine; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine; D011224:Prazosin