Perrott M N, Balment R J
Department of Physiological Sciences, University of Manchester, United Kingdom.
Gen Comp Endocrinol. 1990 Jun;78(3):414-20. doi: 10.1016/0016-6480(90)90030-p.
The changes in arterial blood pressure and plasma cortisol concentration in response to exogenous angiotensin II (AII) and to manipulation of the endogenous renin-angiotensin system (RAS) have been examined in the flounder, Platichthys flesus. Intravenous [Asp1Val5]AII was pressor in a dose-dependent manner over the range of 0.25-250 micrograms/kg. Sequential blood sampling revealed steroidogenic stimulation, measured as change in plasma cortisol concentration, by doses of AII greater than 2.5 micrograms/kg. Enhanced circulating cortisol levels were measured some time after recovery of normal systemic blood pressure, suggesting that the change in plasma steroid concentration was not entirely dependent on the change in systemic blood pressure. Administration of the vasodilator papaverine produced immediate hypotension followed by gradual recovery in blood pressure, which was accompanied by a sustained increment in circulating cortisol. Both blood pressure recovery and the increased plasma steroid concentration were inhibited by prior treatment with the angiotensin converting enzyme inhibitor captopril. These results are consistent with a physiologically important role for the RAS in the control of plasma cortisol levels which complements its demonstrated pressor and dipsogenic actions in the flounder: the RAS may thus afford an integrating influence on the mechanisms of body fluid homeostasis in this euryhaline species.
在比目鱼（欧洲鲽，Platichthys flesus）中，已研究了对外源性血管紧张素II（AII）以及对内源性肾素-血管紧张素系统（RAS）进行调控时动脉血压和血浆皮质醇浓度的变化。静脉注射[天冬氨酸1缬氨酸5]AII在0.25 - 250微克/千克范围内呈剂量依赖性升压。连续采血显示，剂量大于2.5微克/千克的AII可刺激类固醇生成，以血浆皮质醇浓度变化衡量。在全身血压恢复正常一段时间后，测得循环皮质醇水平升高，这表明血浆类固醇浓度的变化并非完全依赖于全身血压的变化。给予血管扩张剂罂粟碱可立即导致低血压，随后血压逐渐恢复，同时循环皮质醇持续增加。血管紧张素转换酶抑制剂卡托普利预先处理可抑制血压恢复以及血浆类固醇浓度升高。这些结果与RAS在控制血浆皮质醇水平方面具有重要生理作用一致，这补充了其在比目鱼中已证实的升压和致渴作用：因此，RAS可能对这种广盐性物种的体液稳态机制产生整合影响。
