Research Paper Volume 1, Issue 9 pp 818—830

Figure 4. Mitochondrial import of the matrix protein ornithine carbamoyltransferase (OCT) is induced to a greater extent after chronic muscle use in young animals. (A) Representative autoradiograms of precursor (pOCT) and mature (mOCT) OCT after 5 and 20 min of the import reaction timecourse in isolated SS (top) and IMF (bottom) mitochondrial subfractions harvested from the control (CON, open bars) and chronically stimulated (STIM, closed bars) limbs of young and old animals (TL, translation lane without mitochondria). (B) and (C) Graphical summaries of the 20 min import data from repeated experiments shown in panel A (n = 9-12). (D) Western blots of MSF-L and HSP90 in isolated cytosolic fractions obtained from the control (C) and chronically stimulated (S) legs of young and old animals. GAPDH was used to confirm equal loading of protein. (E) Summary of repeated experiments shown in panel D (n = 5-7). Data represent the mean ± SEM. * P < 0.05 vs. Young; ¶ P < 0.05 vs. CON.