Sharma V K, Banerjee S P
J Biol Chem. 1978 Aug 10;253(15):5277-9.
The effects of thyroid status on alpha-adrenergic receptors in the rat myocardium were investigated. The potent antagonist [3H]dihydroergokryptine was used to identify alpha-adrenergic receptors in rat heart particulate and sarcolemmal fractions. Administration of triiodothyronine to thyroidectomized rats decreased specific binding to alpha-adrenergic receptors in heart particulate and sarcolemmal fractions by 41% and 45%, respectively. Scatchard analysis revealed that the cardiac sarcolemmal fraction from thyroidectomized rats contained 29.3 fmol/mg of protein, as compared with 17.0 fmol/mg of protein found in the heart preparation of thyroidectomized rats treated with triiodothyronine. The equilibrium dissociation constants for the interaction of receptors with dihydroergokryptine were similar (about 1.5 nM) in the heart sarcolemmal fractions derived from these two groups of rats. The results of this study demonstrate that thyroid hormone can regulate the number of cardiac alpha-adrenergic receptors. In addition, there appears to be a reciprocal relationship between alpha-adrenergic and beta-adrenergic receptors in the rat myocardium.
研究了甲状腺状态对大鼠心肌中α-肾上腺素能受体的影响。使用强效拮抗剂[3H]二氢麦角隐亭来鉴定大鼠心脏微粒体和肌膜组分中的α-肾上腺素能受体。给甲状腺切除的大鼠施用三碘甲状腺原氨酸后，心脏微粒体和肌膜组分中与α-肾上腺素能受体的特异性结合分别降低了41%和45%。Scatchard分析显示，甲状腺切除大鼠的心脏肌膜组分中含有29.3 fmol/mg蛋白质，而用三碘甲状腺原氨酸处理的甲状腺切除大鼠的心脏制剂中含有17.0 fmol/mg蛋白质。这两组大鼠心脏肌膜组分中受体与二氢麦角隐亭相互作用的平衡解离常数相似（约1.5 nM）。本研究结果表明，甲状腺激素可调节心脏α-肾上腺素能受体的数量。此外，大鼠心肌中α-肾上腺素能受体和β-肾上腺素能受体之间似乎存在相互关系。
