What is the Origin of Tissue Anabolic Sensitivity?

This concept is central to understanding resistance training adaptation and aging physiology, where anabolic resistance becomes common. Sensitivity describes the efficiency of the receptor-to-effector cascade within the target cell. It is a crucial factor in determining lean mass retention.

What is the Mechanism of Tissue Anabolic Sensitivity?

Anabolic sensitivity is mediated by the integrity of the intracellular signaling pathways downstream of receptor binding, such as the PI3K/Akt/mTOR pathway. Hormonal status, particularly adequate testosterone and insulin signaling, primes these pathways for activation. Improving sensitivity often involves optimizing nutrient delivery, such as leucine availability, to overcome inherent cellular resistance.

Tissue Anabolic Sensitivity ∞ Area

Tissue Anabolic Sensitivity

Meaning

The responsiveness of peripheral tissues, especially skeletal muscle and bone, to anabolic stimuli such as mechanical load or growth factors like IGF-1 and insulin. High sensitivity means that a smaller stimulus elicits a maximal or near-maximal hypertrophic or repair response. Decreased sensitivity often necessitates higher input levels to achieve adaptation.