TABLE 1.

Fractional urinary amino acid excretion

Amino acid	Fractionala excretion
	xt2+/+b	xt2−/−	Change	ace2+/yc	ace2−1y	Change	coll+/yd	coll−y	Change
	%	%	-fold	%	%	-fold	%	%	-fold
Gly	0.53	51.37	96.25	0.73	0.51	0.69	1.95	82.13	42.19
Ala	0.59	4.49	7.60	0.43	0.69	1.61	0.60	56.42	94.47
Val	0.33	3.50	10.75	0.13	0.07	0.51	0.21	26.36	125.00
Leu	1.23	11.71	9.50	0.45	0.25	0.56	1.55	54.56	35.22
Ile	2.30	8.97	3.90	0.39	0.15	0.37	0.41	36.45	88.31
Met	5.00	33.41	6.68	1.61	1.19	0.74	6.20	58.52	9.43
Ser	0.47	6.66	14.07	2.48	1.77	0.72	1.99	77.69	39.00
Thr	1.04	7.33	7.06	0.57	0.35	0.61	1.55	114.24	73.78
Cys	NDe	ND	ND	ND	ND	ND	ND	ND	ND
Pro	0.33	0.59	1.79	1.71	1.13	0.66	0.46	65.93	144.59
Asn	2.91	6.76	2.33	ND	ND	ND	ND	ND	ND
Gln	0.11	2.94	26.72	0.32	0.32	1.00	0.36	63.69	177.61
Phe	0.39	5.87	15.21	0.87	0.67	0.77	0.52	21.25	40.83
Tyr	0.34	2.14	6.38	0.61	0.49	0.80	1.70	16.45	9.70
Trp	1.97	4.24	2.16	0.30	0.39	1.30	10.99	22.78	2.07
Lys	1.58	2.98	1.88	0.10	0.09	0.88	2.46	4.50	1.83
Arg	ND	ND	ND	ND	ND	ND	ND	ND	ND
His	1.74	9.66	5.56	1.25	1.11	0.89	ND	ND	ND
Asp	2.62	4.12	1.57	ND	ND	ND	ND	ND	ND
Glu	11.46	16.03	1.40	4.05	3.61	0.89	2.17	6.52	3.01

^a Fractional excretion was calculated using an estimate of the glomerular filtration rate of 150 μl/min in females and 240 μl/min in males (21), the measured amino acid concentrations in plasma and urine, and the volume of urine excreted over 24 h.

^b Males, n = 3; females, n = 3.

^c Males, n = 5.

^d Males, n = 3.

^e ND, not determined.