Table 3 -.

Whole body production rates of amino acids and their interconversions

	Healthy (n=20)	COPD (n=23)	P value
Arginine	130.3 (4.3)	114.2 (7.3)	0.71
Citrulline	11.6 (0.6)	14.2 (0.8)	0.03
Glutamate	185.8 (23.3)	211.6 (19.5)	0.46
Glutamine	364.4 (49.8)	316.5 (27.5)	0.38
Glycine	199.7 (13.1)	233.1 (17.9)	0.15
Hydroxyproline	6.1 (0.9)	9.5 (0.5)	0.59
Keto-isocaproic acid	10.2 (0.8)	24.7 (1.2)	0.21
Leucine	80.0 (5.7)	117.2 (7.2)	< 0.0001
Phenylalanine	96.1 (5.1)	90.0 (2.3)	0.23
tau-Methylhistidine	0.47 (0.04)	0.81 (0.1)	0.01
Taurine	21.0 (1.8)	27.1 (2.3)	0.09
Tyrosine	65.6 (4.9)	63.2 (2.1)	0.63
Arginine to citrulline conversion rate (NO production)	4.2 (0.6)	7.2 (0.6)	0.04
Citrulline to arginine conversion rate (ARG de novo production)	14.3 (1.3)	14.1 (1.2)	0.96
Glutamate to glutamine conversion rate	43.5 (8.2)	35.6 (6.2)	0.47
Phenylalanine to tyrosine conversion rate (net protein breakdown)	5.2 (0.7)	4.8 (0.4)	0.73

Values are mean ± SE and expressed as μmol/kg ffm/h Statistics are by unpaired t-test. COPD: chronic obstructive pulmonary disease