Table 2.

Total protein and mRNA expression levels for select mTORC1 signaling and amino acid transporters (mRNA and protein) in the postabsorptive state before and after bed rest in healthy, older adults

	Pre-Bed Rest	Post-Bed Rest	P Value
Total protein
Akt	0.60 ± 0.12	0.65 ± 0.12	0.84
mTOR	1.00 ± 0.28	1.44 ± 0.42	0.03
S6K1	1.22 ± 0.14	1.55 ± 0.25	0.10
4EBP1	0.42 ± 0.05	0.52 ± 0.09	0.13
rpS6	0.68 ± 0.20	0.97 ± 0.33	0.15
ATF4	1.00 ± 0.26	1.12 ± 0.14	0.47
LAT1	0.73 ± 0.23	1.02 ± 0.31	0.10
SNAT2	1.08 ± 0.49	1.41 ± 0.64	0.10
mRNA
LAT1	1.07 ± 0.18	1.77 ± 0.31	0.06
SNAT2	1.15 ± 0.27	1.11 ± 0.30	0.86

Values are means ± SE; n = 6 subjects in each group.

Akt, protein kinase B; mTOR, mammalian target of rapamycin; 4EBP1, 4E binding protein 1; rpS6, ribosomal protein S6; ATF4, activating transcription factor 4; LAT1, L-type amino acid transporter 1; SNAT2, sodium-coupled neutral amino acid transporter 2.

P values were determined from a paired t-test (pre- vs. post-bed rest). Total protein data were calculated by normalizing arbitrary density units to an internal loading control. Postabsorptive mRNA data were determined from the 2^−ΔΔCT method relative to pre-bed rest.