Incorporation of C¹⁴-amino acids into protein of isolated diaphragms: effect of epinephrine and norepinephrine

¹ Department of Physiology, University of Chicago, Chicago, Illinois

When diaphragms isolated from normal rats were incubated with a C¹⁴-amino acid the addition of epinephrine or norepinephrine decreased incorporation of C¹⁴ into muscle protein. The inhibition occurred whether epinephrine was added in vitro or administered in vivo. The minimal effective concentration of epinephrine in vitro was 0.1 µg/ml. When the glucose concentration in the medium was raised to 300 mg % or more the epinephrine induced inhibition of amino acid incorporation into muscle protein was no longer observed.