While physical inactivity poses significant health risks for humans, certain animal species have evolved remarkable adaptations to thrive despite sedentary lifestyles. Among these, the Burmese python (Python bivittatus), a sit-and-wait predator renowned for their capacity to devour massive prey items, stands out for its ability to undergo extreme postprandial muscle growth, even in the absence of physical activity.
Recent findings from our laboratory reveals an unexpected increase in metabolism and protein synthesis in skeletal muscles already within the first few hours after feeding, even before the prey has been digested in the stomach. Using chemical inhibitors targeting the protein degradation systems, we elucidated that this early anabolic response occurs through increased breakdown of endogenous proteins, compensating for the absence of exogenous nutrients.
Our current investigation delves into the mechanisms underlying this metabolic transition. Through blood transfusion experiments, we demonstrate that fasting snakes receiving blood plasma from digesting counterparts, sampled in the pre-absorptive phase of digestion, exhibit elevated skeletal muscle protein synthesis. Furthermore, by sequentially obstructing and/or circumventing different segments of the gastrointestinal tract, we ascertain the pivotal role of the small intestines in the initial stimulation of muscle growth following feeding.
Collectively, our observations suggest that during early digestion, humoral signalling originating from the small intestines triggers the rapid increase in postprandial protein synthesis in the skeletal muscle tissue of the Burmese python. Our findings not only uncover fascinating insights into the Burmese python's unique adaptations but also hold promise for future clinical applications. By revealing the role of humoral signaling from the small intestines in stimulating muscle growth, our research suggests potential avenues for developing therapies to combat muscle wasting disorders in humans, offering hope for patients with conditions such as sarcopenia or cachexia.