What is the Origin of Metabolic Substrate Partitioning?

This concept is fundamental to clinical nutrition and intermediary metabolism. "Metabolic Substrate" refers to the fuel sources the body uses. "Partitioning" describes the directional allocation of these fuels within the body's various tissues. Hormones like insulin and glucagon are the primary directors of this allocation process.

What is the Mechanism of Metabolic Substrate Partitioning?

Insulin plays a dominant role, promoting glucose uptake into muscle and fat cells and inhibiting lipolysis, while simultaneously promoting triglyceride synthesis. Glucagon shifts partitioning toward hepatic glucose output and fat mobilization when energy demands are high. The efficiency of this mechanism dictates long-term body composition, as poor partitioning leads to ectopic lipid deposition and subsequent metabolic dysfunction.

Metabolic Substrate Partitioning

Meaning

The physiological process governed by hormonal signals that determines how ingested macronutrients—carbohydrates, fats, and proteins—are preferentially directed for immediate oxidation, storage as glycogen, or storage as triglycerides within adipose tissue. Optimal partitioning favors oxidation and storage in appropriate depots (e.g., muscle glycogen over visceral fat). This process is central to maintaining insulin sensitivity.