Pang P K, Yang M C, Tenner T E, Chang J K, Shimizu M
J Pharmacol Exp Ther. 1981 Mar;216(3):567-71.
Parathyroid hormone (PTH) and its N-terminal 1-34 fragment were shown to be hypotensive in dogs. In this study, synthetic bovine PTH fragments containing the N-terminal amino acids 1-34, 24-34, 24-28 and 25-27 [bPTH-(1-34), bPTH-(24-34), bPTH-(24-28) and bPTH-(24-27)] were synthesized and tested for hypotensive activity in dogs. bPTH-(1-34) is the most potent of these. The tripeptide is ineffective at doses as high as 2 mg/kg. bPTH-(24-34) and bPTH-(24-28) exhibited hypotensive activity but were less effective than bPTH-(1-34). A decrease in chain length decreased the hypotensive activity. The maximum response produced by bPTH-(1-34) was greater than that of either bPTH-(24-34) or bPTH-(24-28). The maximum responses, however, of bPTH-(24-34) and bPTH-(24-28) were similar. Another striking difference between bPTH-(1-34) and the other two effective fragments was the duration of action. Whereas the action of bPTH-(1-34) at ED50 lasted for up to 6 min the action of bPTH-(24-34) and bPTH-(24-28) lasted for less than 1 min. The hypotensive effect of these three bPTH fragments was not affected by propranolol, phentolamine, atropine, promethazine or cimetidine. In the perfused rat hindlimb, bPTH-(24-28) produced log dose-related sustained vasodilation.
甲状旁腺激素（PTH）及其N端1 - 34片段在犬类中显示出降压作用。在本研究中，合成了包含N端氨基酸1 - 34、24 - 34、24 - 28和25 - 27的合成牛PTH片段[bPTH-(1 - 34)、bPTH-(24 - 34)、bPTH-(24 - 28)和bPTH-(24 - 27)]，并在犬类中测试其降压活性。bPTH-(1 - 34)是其中最有效的。该三肽在高达2mg/kg的剂量下无效。bPTH-(24 - 34)和bPTH-(24 - 28)表现出降压活性，但比bPTH-(1 - 34)效果差。链长的减少降低了降压活性。bPTH-(1 - 34)产生的最大反应大于bPTH-(24 - 34)或bPTH-(24 - 28)。然而，bPTH-(24 - 34)和bPTH-(24 - 28)的最大反应相似。bPTH-(1 - 34)与其他两个有效片段之间的另一个显著差异是作用持续时间。bPTH-(1 - 34)在ED50时的作用持续长达6分钟，而bPTH-(24 - 34)和bPTH-(2,8)的作用持续不到1分钟。这三种bPTH片段的降压作用不受普萘洛尔、酚妥拉明、阿托品、异丙嗪或西咪替丁的影响。在灌注的大鼠后肢中，bPTH-(,8)产生对数剂量相关的持续血管舒张。
