How does cortisol affect the body, particularly in terms of protein metabolism, and what mechanisms lead to protein breakdown and muscle loss during prolonged elevated levels?

High cortisol levels, triggered by stress, significantly impact the breakdown of proteins into amino acids. Cortisol induces a catabolic effect, breaking down muscle protein and diverting amino acids away from muscle absorption. Instead, these amino acids are processed in the liver through deamination, producing ammonia and carbon skeletons.

This process occurs as the body enters survival mode, converting proteins into sugar to meet immediate energy needs. Prolonged high cortisol levels are associated with conditions like autoimmune disease, where the immune system targets healthy tissues. Managing stress to lower cortisol levels is crucial for optimizing protein metabolism and maintaining overall health.