Substrate utilization

Substrate utilization refers to the coordinated physiological process by which cells select and metabolize energy sources, such as glucose, fatty acids, and amino acids, to generate cellular ATP. This process is essential for maintaining energy homeostasis and is tightly regulated by hormonal signals (e.g., insulin) and key metabolic enzymes like pyruvate dehydrogenase (PDH) and carnitine palmitoyltransferase 1 (CPT1) [1, 15]. In many chronic diseases, substrate utilization becomes dysfunctional; for instance, the failing heart often exhibits metabolic inflexibility, characterized by an over-reliance on fatty acid oxidation, which is less oxygen-efficient than glucose oxidation [1, 6]. Therapeutic strategies often involve the use of 'metabolic modulators' designed to shift substrate utilization toward more efficient pathways. Drugs such as trimetazidine and perhexiline target specific metabolic enzymes to favor glucose oxidation, thereby improving cardiac efficiency and mitigating symptoms in ischemic heart disease [1, 2]. Consequently, while not a single molecular target itself, substrate utilization represents a critical physiological phenotype and a major focus for drug discovery in metabolic and cardiovascular medicine [9, 16].

Other names

Metabolic fuel selectionNutrient utilizationSubstrate metabolismFuel utilizationEnergy substrate utilization

Metabolic modulation by shifting metabolic flux (e.g., inhibiting fatty acid oxidation to favor glucose oxidation) to improve oxygen efficiency and reduce accumulation of toxic metabolites [1, 16].