Pang P K, Yang M C, Tenner T E, Kenny A D, Cooper C W
Can J Physiol Pharmacol. 1986 Dec;64(12):1543-7. doi: 10.1139/y86-259.
The involvement of tissue cAMP in the vasodilating action of parathyroid hormone (PTH) was investigated. The bovine active fragment bPTH-(1-34) was used in all studies. In anesthetized dogs, theophylline, a phosphodiesterase inhibitor, potentiated the hypotensive action of bPTH-(1-34) at the dose of 1 microgram/kg. The potentiation was related to the dose of theophylline infused. In an in vitro rat tail artery helical strip assay, dibutyryl cAMP produced dose-related relaxation in arginine vasopressin (AVP) constricted blood vessels. bPTH-(1-34) also produced dose-related relaxation in the tail artery constricted by AVP. In the presence of isobutylmethylxanthine, another phosphodiesterase inhibitor, the bPTH-(1-34) dose--response curve was shifted to the left, indicating potentiation. Imidazole, which has phosphodiesterase stimulating activity, significantly decreased the in vitro vasorelaxing effect of bPTH-(1-34). In addition, bPTH-(1-34) increased significantly the rat tail artery cAMP content. b-PTH-(1-34) oxidized with hydrogen peroxide lost its vasorelaxing activity and was also ineffective in increasing the tail artery cAMP content. All these data strongly suggest that cAMP may be involved in eliciting the vasorelaxing action of bPTH-(1-34).
研究了组织中环磷酸腺苷（cAMP）在甲状旁腺激素（PTH）血管舒张作用中的参与情况。所有研究均使用牛活性片段bPTH-(1-34)。在麻醉犬中，磷酸二酯酶抑制剂茶碱在剂量为1微克/千克时增强了bPTH-(1-34)的降压作用。这种增强作用与注入的茶碱剂量有关。在体外大鼠尾动脉螺旋条试验中，二丁酰cAMP在精氨酸加压素（AVP）收缩的血管中产生剂量相关的舒张作用。bPTH-(1-34)在AVP收缩的尾动脉中也产生剂量相关的舒张作用。在另一种磷酸二酯酶抑制剂异丁基甲基黄嘌呤存在的情况下，bPTH-(1-34)的剂量-反应曲线向左移动，表明有增强作用。具有磷酸二酯酶刺激活性的咪唑显著降低了bPTH-(1-34)的体外血管舒张作用。此外，bPTH-(1-34)显著增加了大鼠尾动脉cAMP含量。用过氧化氢氧化的b-PTH-(1-34)失去了血管舒张活性，并且在增加尾动脉cAMP含量方面也无效。所有这些数据强烈表明，cAMP可能参与引发bPTH-(1-34)的血管舒张作用。
