ABSTRACT
For the last few years, our laboratories have been examining the regulation of protein synthesis in muscle and adipose tissue by amino acids. Knowledge of this regulation is by no means new. Groups including Buse,1-7 Morgan,8,9 Tischler,10,11 and Goldberg12 recognized the ability of amino acids to regulate protein synthesis (and their ability to modify insulin effects on protein synthesis) in the mid-1970s and early 1980s. In both muscle and fat, amino acids stimulate protein synthesis, both independently and additively, with growth factors such as insulin and insulin-like growth factors (IGF). The presence of amino acids facilitates the ability of insulin to stimulate protein synthesis, and conversely the presence of insulin appears to facilitate the ability of amino acids to stimulate protein synthesis.
