The biochemistry and physiology of myoglobin are studied through the application of immunological techniques. Synthesis of ths oxygen-binding, heme protein of muscle is detected in muscle tissue culture using specific antibody to assess incorporation of isotope-tracer labelled precursors. Understanding the influence of maturity, environment and the nervous system upon the ability of muscle to produce this protein is one of this project's major goals. Immunological methods are also used to identify and measure myoglobin in body fluids. This protein has been found in the circulation in association with skeletal and cardiac muscle disease and its quantification has proven useful in the assesssment of the presence and severity of human myopathy. Antibody techniques are the most sensitive and specific available for this purpose.