%0 Journal Article %A H. Grasemann %A C. Grasemann %A F. Kurtz %A G. Tietze-Schillings %A U. Vester %A F. Ratjen %T Oral L-arginine supplementation in cystic fibrosis patients: a placebo-controlled study %D 2005 %R 10.1183/09031936.04.00086104 %J European Respiratory Journal %P 62-68 %V 25 %N 1 %X Exhaled nitric oxide (eNO) is decreased in cystic fibrosis (CF). The effect of oral L-arginine, the precursor of enzymatic nitric oxide (NO) formation, on airway NO in patients with CF was studied. In a pilot study, oral L-arginine was given in a single dose of 200 mg·kg−1 body weight to eight healthy controls and eight CF patients. Subsequently, the same L-arginine dose was given to 10 patients with CF (five females) t.i.d. for 6 weeks in a randomised double-blind placebo-controlled crossover study. A single dose of oral L-arginine resulted in a 5.5-fold increase of L-arginine in plasma and a 1.3-fold increase of L-arginine in sputum after 2 h. Maximum eNO, within 3 h of L-arginine intake, increased significantly in both CF patients (5.4±2.1 ppb versus 8.3±3.5 ppb) and controls (18.0±8.1 ppb versus 26.4±12.3 ppb). Supplementation of L-arginine for 6 weeks resulted in a sustained increase in eNO compared to placebo (9.7±5.7 ppb versus 6.3±3.1 ppb). An effect of L-arginine supplementation on forced expiratory volume in one second was not observed. These data indicate that airway nitric oxide formation in cystic fibrosis patients can be augmented with oral L-arginine supplementation. %U https://erj.ersjournals.com/content/erj/25/1/62.full.pdf