Differential Regulation of Amino Acid Exchange and protein Dynamics Across Splanchnic and Skeletal Muscle Beds by Insulin in Healthy Human Subjects

摘要

To define the mechanism of insulin's anticatabolic action, the effects of three different dosages of insulin (0.25, 0.5, and 1.0 mU.kg~-1. Min~-1) versus saline on pro- tein dynamics across splanchnic and skeletal muscle (leg) beds were determined using stable isotopes of phenylalanine, tyrosine, and leucine in 24 healthy sub- jects. After an overnight fast, protein breakdown in muscle exceeded protein synthesis, causing a net release of amino acids form muscle bed, while in the splanchnic bed protein synthesis exceeded protein breakdown, resulting in a net uptake of these amino acids.