Fig. 2.

Cardiac metabolism in isolated working hearts. Cardiac metabolism was measured in hearts isolated from 14 to 16 week-old male WT and LpL^GPI mice in the presence or absence of myriocin (n = 5 per genotype). All hearts were prepared and perfused in the working mode. Palmitate oxidation (A) was determined in separate perfused hearts by measuring the amount of ³H₂O released from [9,10-³H]palmitate. Glucose oxidation (B) was determined by trapping and measuring ¹⁴CO₂ released by the metabolism of [¹⁴C]glucose, and glycolysis (C) was determined by measuring the amount of ³H₂O released from the metabolism of exogenous [5-³H]glucose. Cardiac power (D) was measured in hearts in which palmitate and glucose oxidation rates were determined (n = 5 each group). MVO₂ (E) and cardiac efficiency (F) were measured during palmitate oxidation. *P < 0.05 versus WT; ^§P < 0.05 versus LpL^GPI.