Raff H, Shinsako J, Wade C E, Keil L C, Dallman M F
Am J Physiol. 1985 Nov;249(5 Pt 2):R611-6. doi: 10.1152/ajpregu.1985.249.5.R611.
This study examined the plasma aldosterone and corticosteroid responses to a 60-min infusion of adrenocorticotropin (ACTH) or angiotensin (ANG) II started immediately after an acute isotonic saline volume expansion (0.5 ml . kg-1 . min-1 for 30 min). Five conscious dogs of either sex with exteriorized carotid loops were used in this repeated-design study. Volume expansion per se caused a 10% decrease in hematocrit, a 12.5% decrease in plasma protein, and a 2.7-mmHg increase in central venous pressure with no change in mean arterial pressure, heart rate, or plasma sodium. Volume expansion per se also resulted in significant reductions in vasopressin, plasma renin activity, ACTH, aldosterone, and corticosteroid levels. The aldosterone responses to ACTH and ANG II were significantly inhibited (46-71%) by acute volume expansion. The corticosteroid response to ACTH was 19-29% inhibited by volume expansion. We conclude that acute volume expansion significantly inhibits the adrenocortical sensitivity to its tropic hormones probably via alterations of synergistic factors.
本研究检测了急性等渗盐水扩容（以0.5 ml·kg-1·min-1的速度输注30分钟）后立即开始的60分钟促肾上腺皮质激素（ACTH）或血管紧张素（ANG）II输注过程中血浆醛固酮和皮质类固醇的反应。在这项重复设计研究中，使用了5只具有外露颈动脉袢的雌雄不限的清醒犬。扩容本身导致血细胞比容降低10%，血浆蛋白降低12.5%，中心静脉压升高2.7 mmHg，而平均动脉压、心率或血浆钠水平无变化。扩容本身还导致血管加压素、血浆肾素活性、ACTH、醛固酮和皮质类固醇水平显著降低。急性扩容显著抑制了醛固酮对ACTH和ANG II的反应（46 - 71%）。扩容对ACTH的皮质类固醇反应有19 - 29%的抑制作用。我们得出结论，急性扩容可能通过协同因子的改变显著抑制肾上腺皮质对其促激素的敏感性。
