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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.