TABLE 4.

Amino acids, urea, and carbon dioxide kinetics in partial– and null–ornithine transcarbamylase–deficient (partial- and null-OTCD) subjects who received treatment with sodium phenylbutyrate (10 g · m⁻² · d⁻¹) or phenylbutyrate plus branched-chain amino acid (BCAA) supplementation¹

	Partial-OTCD subjects (n = 7)2		Null-OTCD subjects (n = 3)2			P values
Item	Phenylbutyrate	BCAA	Phenylbutyrate	BCAA	Pooled SEM3	TRT	Gen	TRT × Gen
Flux (μmol · kg−1 · h−1)
Urea	121	117	99	82	21.7	<0.575	<0.145	<0.736
Phenylalanine	43	44	41	41	2.8	<0.550	<0.805	<0.794
Tyrosine	45	46	49	41	3.4	<0.466	<0.815	<0.344
Leucine	127	162	106	147	16.5	<0.096	<0.407	<0.902
Glutamine	263	298	302	298	26.7	<0.286	<0.242	<0.947
CO2 (×100)	134	138	131	132	15.8	<0.900	<0.829	<0.963
Rate of conversion (μmol · kg−1 · h−1)
Gln→urea	19	26	27	31	6.5	<0.376	<0.290	<0.796
Phe→Tyr	8	8	8	7	1.3	<0.753	<0.852	<0.510
Leu→CO2	44	56	28	39	4.6	<0.093	<0.026	<0.923

¹TRT, treatment (phenylbutyrate compared with phenylbutyrate plus BCAA treatments); Gen, genotype (partial-OTCD compared with null-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).

²Values are means.

³On the basis of n = 7.