Skip to main content

Table 3 Plasma phenylalanine concentrations and enrichments and muscle free and protein-bound phenylalanine enrichments during basal, postabsorptive conditions and during the hyperinsulinemic-hyperaminoacidemic clamp in young and old men

From: Sexually dimorphic effect of aging on skeletal muscle protein synthesis

Time (min) Concentration Enrichment
  (μM) Muscle protein bound TTR Muscle free TTR Plasma TTR
  Young Old Young Old Young Old Young Old
Basal conditions       
60 59 ± 8 64 ± 9 0.000033 ± 0.000007 0.000101 ± 0.000026 0.0488 ± 0.0037 0.0545 ± 0.0044 0.0921 ± 0.0055 0.0929 ± 0.0066
90 48 ± 6 67 ± 8 --- --- --- --- 0.1030 ± 0.0077 0.0993 ± 0.0090
120 58 ± 9 63 ± 8 --- --- --- --- 0.1032 ± 0.0056 0.1119 ± 0.0093
150 53 ± 9 61 ± 9 --- --- --- --- 0.1118 ± 0.0119 0.1130 ± 0.0067
180 56 ± 10 63 ± 9 --- --- --- --- 0.1088 ± 0.0034 0.1129 ± 0.0056
210 60 ± 7 66 ± 8 --- --- --- --- 0.1093 ± 0.0031 0.1155 ± 0.0078
240 59 ± 8 64 ± 9 0.000099 ± 0.000009 0.000186 ± 0.000029 0.0589 ± 0.0027 0.0686 ± 0.0048 0.1065 ± 0.0032 0.1194 ± 0.0079
Δ (240 – 60 min) 0.000067 ± 0.000009 0.000085 ± 0.000013     
Mean 56 ± 7 64 ± 8    0.0539 ± 0.0028 0.0615 ± 0.0041 0.1050 ± 0.0051 0.1093 ± 0.0071
Hyperinsulinemic-hyperaminoacidemic clamp      
270 93 ± 14 97 ± 10 --- --- --- --- 0.0969 ± 0.0031 0.1108 ± 0.0045
300 88 ± 12 97 ± 10 --- --- --- --- 0.0958 ± 0.0034 0.1028 ± 0.0042
330 116 ± 18 107 ± 14 --- --- --- --- 0.0942 ± 0.0022 0.1005 ± 0.0050
360 85 ± 10 121 ± 14 --- --- --- --- 0.0950 ± 0.0025 0.1000 ± 0.0044
390 98 ± 12 128 ± 16 --- --- --- --- 0.0937 ± 0.0013 0.1021 ± 0.0055
420 108 ± 14 116 ± 17 0.000235 ± 0.000023 0.000310 ± 0.000038 0.0719 ± 0.0030 0.0806 ± 0.0033 0.0960 ± 0.0019 0.0952 ± 0.0055
Δ (420 – 240 min) 0.000136 ± 0.000015 0.000124 ± 0.000020     
Mean 98 ± 12 111 ± 12    0.0654 ± 0.0027 0.0746 ± 0.0038 0.0953 ± 0.0021 0.1019 ± 0.0043
  1. Values are means ± SEM.