studies showing significant regression of CAC and contemporaneous data showing opposite results. 3-6 Several randomized controlled clinical trials have failed to show attenuation of progression of CAC despite a significant lowering of low-density lipoprotein cholesterol (LDL-C) by atorvastatin or pravastatin. 7-11 Pitavastatin has been reported to substantially reduce LDL-C, as have other statins. 12 A previous study showed a significant increase in T he prevalence of coronary artery calcification (CAC) is age and sex dependent, occurring in ≥90% of men and ≥67% of women aged >70 years. Background: The effect of lipid-lowering agents on progression of coronary artery calcification (CAC) remains unclear. We evaluated the effects of pitavastatin 2 mg/day (PIT2), pitavastatin 4 mg/day (PIT4), and PIT2 combined with eicosapentaenoic acid (PIT2+EPA) on CAC progression.

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The steady-state reactant levels of triose-phosphate isomerase and the glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase system were examined in guinea-pig cardiac muscle. Key glycolytic intermediates, including glyceraldehyde 3-phosphate were directly measured and compared with those of creatine kinase. Nonworking Langendorff hearts as well as isolated working hearts were perfused with 5 mM glucose (plus insulin) under normoxia conditions to maintain lactate dehydrogenase near-equilibrium. The cytosolic phosphorylation[Pi])) was derived from creatine kinase and the free [NAD+]/( [NADH] . [H']) ratio from lactate dehydrogenase. In Langendorff hearts glycolysis was varied from near-zero flux (hyperkalemic cardiac arrest) to higher than normal flux (normal and maximum catecholamine stimulation). The triose-phosphate isomerase was near-equilibrium only in control or potassium-arrested Langendorff hearts as well as in postischemic 'stunned' hearts. However, when glycolytic flux increased due to norepinephrine or due to physiological pressurevolume work the enzyme was displaced from equilibrium. C3. min-' . g dry mass-'). However, the equality between the two phosphorylation ratios was not abolished upon resumption of spontaneous beating and also not during adrenergic stimulation (flux % 5 -14 pmol C3 . min-' . g dry mass-'). In contrast, when flux increased due to transition from no-work to physiological pressurevolume work (rate increase from % 3 to 11 pmol C3 . min-' g dry inass-'), the two ratios were markedly different indicating disequilibrium of the glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase. Only during adrenergic stimulation or postischemic myocardial 'stunning', not due to hydraulic work load per se, glyceraldehyde-3-phosphate levels increased from about 4 pM to 2 16 pM. Thus the guinea-pig cardiac glyceraldehyde-3-phosphate dehydrogenase/phosphoglyceratc kinase system can realize the potential for nearequilibrium catalysis at significant flux provided glyceraldehyde-3-phosphate levels rise, e.g., due to 'stunning' or adrenergic hormones. Triose-phosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinasc, lactate dehydrogenase, and creatine kinase are powerful enzyme systems in the myocardium [I, 21. In heart, skeletal muscle, and brain the lactate dehydrogenase and the creatine kinase systems are considered near-equilibrium during metabolic steady states in which net fluxes are small compared to the unidirectional fluxes [3 -1 I]. However, the thermodynamic states of trioscphosphate isomerase and the combined glyceraldehyde-3-phosphate dehydrogenaselphosphoglycerate kinase reaction are controversial as far as rat liver is concerned [5,[12][13][14]. Uncertainty regarding the condition of glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase prevails also in regard to rat and guinea-pig cardiac muscle [3,15, 161. The glyceraldehyde-3-phosphate dehydrogenase, not the phosphoglycerate kinase, appears to be out of equilibrium in hepa...

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