TABLE 2.

Amino acids, urea, and carbon dioxide kinetics in healthy control and partial–ornithine transcarbamylase–deficient (partial-OTCD) subjects who received either control or sodium phenylbutyrate (10 g · m⁻² · d⁻¹) treatment¹

	Control subjects (n = 7)2		Partial-OTCD subjects (n = 7)2			P values
Item	Control	Phenylbutyrate	Control	Phenylbutyrate	Pooled SEM	TRT	Gen	TRT × Gen
Flux (μmol · kg−1 · h−1)
Urea	180	156	157	121	11.0	<0.012	<0.017	<0.600
Phenylalanine	49	50	46	43	2.9	<0.778	<0.062	<0.503
Tyrosine	44	51	47	45	3.0	<0.358	<0.738	<0.169
Leucine	114	128	114	127	8.7	<0.467	<0.432	<0.371
Glutamine	266	299	281	263	19.3	<0.709	<0.587	<0.201
CO2 (×100)	143	135	140	134	13.2	<0.607	<0.895	<0.932
Clearance (mL plasma/min)
Phenylalanine	10.5	11.7	10.1	9.2	0.77	<0.800	<0.180	<0.014
Tyrosine	11.5	11.7	9.7	8.5	1.2	<0.583	<0.129	<0.426
Leucine	14.5	23.7	17.2	25.0	2.69	<0.001	<0.539	<0.736
Glutamine	7.8	9.2	6.6	6.7	0.65	<0.082	<0.051	<0.116
Rate of conversion (μmol · kg−1 · h−1)
Gln→urea	45a	33a,b	51a	22b	4.6	<0.001	<0.711	<0.011
Phe→Tyr	7	8	8	8	0.6	<0.980	<0.377	<0.403
Leu→CO2	43	45	46	44	3.7	<0.903	<0.816	<0.578

¹TRT, treatment (control compared with phenylbutyrate treatments); Gen, genotype (control compared with partial-OTCD subjects); TRT × Gen, interaction of main effects; Gln→urea, rate of transfer of the amido group of glutamine to urea; Phe→Tyr, rate of conversion of phenylalanine to tyrosine; Leu→CO₂, rate of conversion of leucine to carbon dioxide. Data were analyzed by using mixed models (fixed effects for TRT, Gen, and TRT × Gen; random effects for subject). Values with different superscript letters differed (Tukey-Kramer–adjusted P < 0.05).

²Values are means.