Kelly J J, Williamson P, Martin A, Whitworth J A
Department of Renal Medicine, University of New South Wales, St George Hospital, Sydney, Australia.
J Hypertens. 2001 Feb;19(2):263-8. doi: 10.1097/00004872-200102000-00013.
The aim of this study was to determine whether cortisol-induced hypertension can be reversed by co-administration of oral L-arginine.
Three studies were undertaken in healthy male human subjects. The first study addressed the effect of oral L-arginine loading on plasma arginine concentration. Study 2 addressed the effect of co-administration of cortisol with L-arginine on plasma L-arginine concentrations. Study 3 was a randomized placebo crossover control comparing the effects of cortisol 80 mg/day co-administered with a placebo to cortisol 80 mg/day co-administered with L-arginine 21 g/day.
Blood pressure was measured by a random Hawksley sphygmomanometer. Plasma nitrate/nitrite concentrations were measured by a modified Greiss reaction. Plasma arginine and citrulline concentrations were measured by an automated amino acid analyser.
Plasma arginine concentrations were doubled by oral doses of 15 g/day and 21 g/day of L-arginine (study 1). Co-administration of cortisol did not alter plasma arginine concentrations in subjects taking 21 g of L-arginine per day (study 2). Co-administration of L-arginine 21 g/day with cortisol 80 mg/day did not prevent cortisol-induced increases in blood pressure or cortisol-induced falls in plasma nitrate/nitrite concentrations.
Cortisol-induced hypertension is accompanied by a fall in plasma nitrate/nitrite concentrations. Oral L-arginine administration does not prevent cortisol-induced falls in plasma nitrate/nitrite concentrations or increases in blood pressure. We propose that cortisol-induced reductions in nitrate/nitrite production occur at a point distal to L-arginine availability in the nitric oxide synthase pathway.
本研究旨在确定口服L-精氨酸联合使用是否能逆转皮质醇诱导的高血压。
对健康男性受试者进行了三项研究。第一项研究探讨口服L-精氨酸负荷对血浆精氨酸浓度的影响。研究2探讨皮质醇与L-精氨酸联合使用对血浆L-精氨酸浓度的影响。研究3是一项随机安慰剂交叉对照研究，比较每天80毫克皮质醇与安慰剂联合使用和每天80毫克皮质醇与21克L-精氨酸联合使用的效果。
使用随机的Hawksley血压计测量血压。通过改良的格里斯反应测量血浆硝酸盐/亚硝酸盐浓度。使用自动氨基酸分析仪测量血浆精氨酸和瓜氨酸浓度。
每天口服15克和21克L-精氨酸可使血浆精氨酸浓度增加一倍（研究1）。对于每天服用21克L-精氨酸的受试者，联合使用皮质醇不会改变血浆精氨酸浓度（研究2）。每天21克L-精氨酸与80毫克皮质醇联合使用并不能预防皮质醇诱导的血压升高或皮质醇诱导的血浆硝酸盐/亚硝酸盐浓度下降。
皮质醇诱导的高血压伴有血浆硝酸盐/亚硝酸盐浓度下降。口服L-精氨酸不能预防皮质醇诱导的血浆硝酸盐/亚硝酸盐浓度下降或血压升高。我们认为，皮质醇诱导的硝酸盐/亚硝酸盐生成减少发生在一氧化氮合酶途径中L-精氨酸可用性的远端。
