Figure 5.

Forced expression of PGC-1 in neonatal cardiac myocytes increases oxygen consumption and coupled respiration. (a) Oxygen-consumption rates assessed in saponin-permeabilized cultured rat neonatal cardiac myocytes under conditions in which mitochondrial substrate and ADP were not limiting. The bars represent mean (± SE) oxygen consumption rates (nanomole of oxygen per minute per milligram of protein) in cells infected with control adenovirus expressing GFP alone (C) or adenovirus expressing GFP and PGC-1 (P), corrected for total cellular protein content (^AP < 0.05). The values represent four samples in two independent experiments. (b) Myocyte oxygen-consumption rates in serum-free growth medium (without saponin) at base line and after exposure to the ATP synthase inhibitor, oligomycin. The values represent the mean of at least three samples in two independent experiments (^AP < 0.001). (c) Representative autoradiograph of Northern blot analyses performed with total RNA isolated from cultured rat neonatal cardiac myocytes after a 48-hour exposure to three different conditions: uninfected cells (U), cells infected with control adenovirus expressing GFP alone (C), and cells infected with adenovirus expressing both GFP and PGC-1 (P). The blot was hybridized to cDNA probes encoding UCP-2, UCP-3, and the ATP synthase β subunit. The ethidium bromide–stained 28S ribosomal subunit (28S) was used as a control for lane loading.