Proto M C, Coviello A, Khosla M C, Bumpus F M
Hypertension. 1983 Nov-Dec;5(6 Pt 3):V101-4. doi: 10.1161/01.hyp.5.6_pt_3.v101.
The role of frog-skin angiotensin II (AII) in amphibia was studied by comparing the sodium and water permeability effects of three angiotensins (AII): frog skin (Ala-Pro-Gly-[Ile3, Val5]-Ang II), human [( Asp1, Ile5]-AII), and Japanese goosefish [( Asn1-Val5]-AII). Frog-skin AII increased the short-circuit current (SCC) significantly after it was added to the dermal side of the isolated skin of the South American frogs, Leptodactylus chaquensis and ocellatus, and the toad, Bufo arenarum, in concentrations of 10(-6) M. In frogs, the effect was significant at 15 minutes and reached 45% over control after 2 1/2 hours. The effect cannot be achieved with concentrations lower than 10(-7) M. Since amiloride (10(-4) M) blocked the SCC response, and absence of chloride in the bathing fluid did not, the effect is probably dependent on sodium transport. Human AII (10(-6) M) produced a similar response in summer frogs that had been treated with 0.1% NaCl for 14 days. Goosefish AII was ineffective at similar concentrations, and none of the angiotensins modified SCC in the toad bladder. Hydrosmotic effects could be achieved with the three angiotensins, the response being dependent on seasonal and species factors but always considerably lower than that of the neurohypophyseal peptides. Vascular reactivity of the isolated frog hindlimbs was compared by dose-response curves. Potency ratios on a molar basis against frog-skin AII was 1.136 for human AII and 1.193 for goosefish AII. The results show that the effects of the angiotensins differ in both the response of SCC to frog-skin angiotensin and its higher vascular effects.
通过比较三种血管紧张素（AII）对蛙皮钠和水通透性的影响，研究了蛙皮血管紧张素II（AII）在两栖动物中的作用：蛙皮血管紧张素（Ala-Pro-Gly-[Ile3, Val5]-Ang II）、人血管紧张素[（Asp1, Ile5]-AII）和日本海鲶血管紧张素[（Asn1-Val5]-AII）。将蛙皮血管紧张素以10⁻⁶ M的浓度添加到南美蛙Leptodactylus chaquensis和ocellatus以及蟾蜍Bufo arenarum的离体皮肤真皮侧后，蛙皮血管紧张素显著增加了短路电流（SCC）。在蛙中，15分钟时效应显著，2个半小时后比对照增加了45%。浓度低于10⁻⁷ M时无法产生该效应。由于氨氯地平（10⁻⁴ M）阻断了SCC反应，而浴液中无氯离子时则不会，因此该效应可能依赖于钠转运。人血管紧张素（10⁻⁶ M）在经0.1% NaCl处理14天的夏季蛙中产生了类似反应。海鲶血管紧张素在类似浓度下无效，且所有血管紧张素均未改变蟾蜍膀胱的SCC。三种血管紧张素均可产生水渗透效应，其反应依赖于季节和物种因素，但始终远低于神经垂体肽的效应。通过剂量反应曲线比较了离体蛙后肢的血管反应性。以摩尔计，人血管紧张素相对于蛙皮血管紧张素的效价比为1.136，海鲶血管紧张素为1.193。结果表明，血管紧张素在SCC对蛙皮血管紧张素的反应及其更高的血管效应方面的作用存在差异。
