TABLE 4.

Free phenylalanine concentrations and enrichments in the femoral artery and vein and in the muscle tissue of the 2 groups of healthy elderly subjects during supplementation with either 18 g essential amino acids or 40 g balanced amino acids¹

	18 g Essential amino acids (n = 6)		40 g Balanced amino acids (n = 8)		P (ANOVA)
	Basal state	Supplementation	Basal state	Supplementation	Group effect	Supplement effect	Interaction
Concentration (μmol/L)
Artery	68 ± 4	148 ± 15	59 ± 2	120 ± 8	0.0455	< 0.0001	0.26
Vein	74 ± 4	140 ± 12	65 ± 3	115 ± 8	0.0414	< 0.0001	0.32
Muscle	96 ± 9	149 ± 10	130 ± 12	195 ± 16	0.0433	< 0.0001	0.51
Enrichment (tracer-tracee ratio × 100)
Intravenous tracer
Artery	8.21 ± 0.21	4.73 ± 0.28	7.91 ± 0.60	4.93 ± 0.27	0.92	< 0.0001	0.41
Vein	5.99 ± 0.27	4.19 ± 0.23	6.22 ± 0.55	4.41 ± 0.30	0.66	< 0.0001	0.98
Muscle	5.04 ± 0.27	4.03 ± 0.18	4.82 ± 0.69	3.82 ± 0.32	0.72	0.0055	0.98
Oral tracer
Artery	—	5.30 ± 0.29	—	5.17 ± 0.13	0.89	—	—

¹x̄ ± SE.