Premen A J
Department of Physiology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799.
Regul Pept. 1988 May;21(1-2):57-67. doi: 10.1016/0167-0115(88)90091-2.
Glucagon has been suggested to be involved in the pathway by which protein and amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR) postprandially. Recent data suggest that amino acids elevate RBF and GFR through an autoregulatory mechanism (i.e., by impairing renal autoregulation). If glucagon mediates the renal hemodynamic effects of amino acids, 'physiologic' infusion of glucagon would also be expected to impair autoregulation. We examined the effects of glucagon (5 ng/kg per min given intraportally and intravenously) on RBF and GFR autoregulation in anesthetized dogs. Intraportal glucagon (n = 6) increased RBF (24%) and GFR (23%) at normal arterial pressure. RBF and GFR were well autoregulated (greater than 90% of control) at renal arterial pressures greater than or equal to 85 mm Hg before and after glucagon. At 70 mm Hg, RBF and GFR decreased by 15 and 16%, respectively, before glucagon and by 19 and 22%, respectively, after glucagon. Intravenous glucagon (n = 6) produced similar effects. Intraportal glucagon at 500 ng/kg per min increased RBF (35%), heart rate (69%) and plasma glucose (78%) and decreased arterial pressure (16%) (GFR not measured). This dose impaired RBF autoregulation by 30%. The data suggest that a 'physiologic' dose of glucagon increases renal hemodynamics without impairing renal autoregulation. It is suggested that glucagon's vasodilatory effect on the renal vasculature may be additive to the renal effects of amino acids.
有人提出，胰高血糖素参与了蛋白质和氨基酸在餐后提高肾血流量（RBF）和肾小球滤过率（GFR）的途径。最近的数据表明，氨基酸通过一种自身调节机制（即通过损害肾自身调节）来提高RBF和GFR。如果胰高血糖素介导氨基酸对肾血流动力学的影响，那么“生理剂量”的胰高血糖素也可能会损害自身调节。我们研究了胰高血糖素（经门静脉和静脉内给予5 ng/kg每分钟）对麻醉犬RBF和GFR自身调节的影响。经门静脉给予胰高血糖素（n = 6）在正常动脉压下可使RBF增加24%，GFR增加23%。在给予胰高血糖素前后，当肾动脉压大于或等于85 mmHg时，RBF和GFR得到良好的自身调节（大于对照组的90%）。在70 mmHg时，给予胰高血糖素前RBF和GFR分别下降15%和16%，给予后分别下降19%和22%。静脉内给予胰高血糖素（n = 6）产生类似的效果。经门静脉给予500 ng/kg每分钟的胰高血糖素可使RBF增加35%、心率增加69%、血糖增加78%，并使动脉压下降16%（未测量GFR）。该剂量使RBF自身调节受损30%。数据表明，“生理剂量”的胰高血糖素可增加肾血流动力学而不损害肾自身调节。提示胰高血糖素对肾血管的舒张作用可能与氨基酸对肾的作用相加。
