Table 3.
Protein FBRs in rats
| Tissue/Protein | FBR, %/day |
|---|---|
| Skeletal muscle | |
| Myofibrillar, soleus | 3.35 ± 0.79 |
| Myofibrillar, EDL | 3.27 ± 0.66 |
| Collagen, soleus | 2.99 ± 0.66 |
| Heart muscle, left ventricle | |
| Myofibrillar | 5.30 ± 0.88 |
| Collagen | 3.64 ± 0.61 |
| Tendon, collagen, patella | 0.66 ± 0.28 |
| Liver, nonsoluble mix | 5.00 ± 1.50 |
Values are means ± SE. FBR, fractional breakdown rate; EDL, extensor digitorum longus. The FBR values are the slopes of the linear relation between the log-transformed 2H alanine enrichments determined on days 0, 1, 2, and 4. The soleus muscle in rats consists of 80% myosin heavy chain (MHC) I, and the remaining 20% is MHC IIa, whereas EDL consists of 10% MHC IIa and 90% MHC IIb/x fiber type II. The mixed liver proteins were the nonsoluble proteins pelleted by centrifugation after homogenization.