NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands; and.
Institute of Sports and Exercise Studies, HAN University of Applied Sciences, Nijmegen, The Netherlands.
J Appl Physiol (1985). 2017 Sep 1;123(3):637-644. doi: 10.1152/japplphysiol.01036.2016. Epub 2017 Jun 29.
Nitrate ([Formula: see text]) ingestion has been shown to have vasoactive and ergogenic effects that have been attributed to increased nitric oxide (NO) production. Recent observations in rodents suggest that skeletal muscle tissue serves as an endogenous [Formula: see text] "reservoir." The present study determined [Formula: see text] contents in human skeletal muscle tissue in a postabsorptive state and following ingestion of a sodium nitrate bolus (NaNO). Seventeen male, type 2 diabetes patients (age 72 ± 1 yr; body mass index 26.5 ± 0.5 kg/m; means ± SE) were randomized to ingest a dose of NaNO (NIT; 9.3 mg [Formula: see text]/kg body wt) or placebo (PLA; 8.8 mg NaCl/kg body wt). Blood and muscle biopsy samples were taken before and up to 7 h following [Formula: see text] or placebo ingestion to assess [Formula: see text] [and plasma nitrite ([Formula: see text])] concentrations. Additionally, basal plasma and muscle [Formula: see text] concentrations were assessed in 10 healthy young (CON-Y; age 21 ± 1 yr) and 10 healthy older (CON-O; age 75 ± 1 yr) control subjects. In all groups, baseline [Formula: see text] concentrations were higher in muscle (NIT, 57 ± 7; PLA, 61 ± 7; CON-Y, 80 ± 10; CON-O, 54 ± 6 µmol/l) than in plasma (NIT, 35 ± 3; PLA, 32 ± 3; CON-Y, 38 ± 3; CON-O, 33 ± 3 µmol/l; ≤ 0.011). Ingestion of NaNO resulted in a sustained increase in plasma [Formula: see text], plasma [Formula: see text], and muscle [Formula: see text] concentrations (up to 185 ± 25 µmol/l) in the NIT group (time effect < 0.001) compared with PLA (treatment effect < 0.05). In conclusion, basal [Formula: see text] concentrations are substantially higher in human skeletal muscle tissue compared with plasma. Ingestion of a bolus of dietary [Formula: see text] increases both plasma and muscle [Formula: see text] contents in humans. Literature of the pharmacokinetics following dietary nitrate ingestion is usually limited to the changes observed in plasma nitrate and nitrite concentrations. The present investigation assessed the skeletal muscle nitrate content in humans during the postabsorptive state, as well as following dietary nitrate ingestion. We show that basal nitrate content is higher in skeletal muscle tissue than in plasma and that ingestion of a dietary nitrate bolus strongly increases both plasma and muscle nitrate concentrations.
硝酸盐（[化学式：见正文]）的摄入已被证明具有血管活性和增强体力的作用，这归因于一氧化氮（NO）产量的增加。最近在啮齿动物中的观察表明，骨骼肌组织是内源性[化学式：见正文]“储备库”。本研究在吸收后状态下和摄入硝酸钠丸（NaNO）后确定了人类骨骼肌组织中的[化学式：见正文]含量。17 名男性，2 型糖尿病患者（年龄 72 ± 1 岁；体重指数 26.5 ± 0.5 kg/m；平均值 ± SE）被随机分为摄入剂量的 NaNO（NIT；9.3 mg [化学式：见正文]/kg 体重）或安慰剂（PLA；8.8 mg NaCl/kg 体重）。在[化学式：见正文]或安慰剂摄入前和最多 7 小时内采集血液和肌肉活检样本，以评估[化学式：见正文] [和血浆亚硝酸盐（[化学式：见正文]）]浓度。此外，在 10 名健康的年轻（CON-Y；年龄 21 ± 1 岁）和 10 名健康的老年（CON-O；年龄 75 ± 1 岁）对照组受试者中评估了基础血浆和肌肉[化学式：见正文]浓度。在所有组中，基线[化学式：见正文]浓度在肌肉中（NIT，57 ± 7；PLA，61 ± 7；CON-Y，80 ± 10；CON-O，54 ± 6 µmol/l）高于血浆中（NIT，35 ± 3；PLA，32 ± 3；CON-Y，38 ± 3；CON-O，33 ± 3 µmol/l； ≤ 0.011）。与 PLA 相比，摄入 NaNO 导致血浆[化学式：见正文]、血浆[化学式：见正文]和肌肉[化学式：见正文]浓度持续增加（高达 185 ± 25 µmol/l）在 NIT 组（时间效应 ＜0.001）（治疗效应 ＜0.05）。总之，与血浆相比，人类骨骼肌组织中的基础[化学式：见正文]浓度明显更高。摄入膳食[化学式：见正文]丸会增加人体的血浆和肌肉[化学式：见正文]含量。关于饮食硝酸盐摄入后的药代动力学的文献通常仅限于观察到的血浆硝酸盐和亚硝酸盐浓度的变化。本研究评估了人类在吸收后状态以及饮食硝酸盐摄入后的骨骼肌硝酸盐含量。我们表明，基础硝酸盐含量在骨骼肌组织中高于血浆，并且摄入膳食硝酸盐丸强烈增加了血浆和肌肉硝酸盐浓度。
