An Oral Tyrosine Tolerance Test in Thyrotoxicosis and Myxedema

Abstract

IN patients with thyrotoxicosis the concentration of tyrosine in plasma has been shown to increase^{1 , 2} whereas concentrations of other amino acids except glutamic acid have been normal.³ When loads of tyrosine were fed to hyperthyroid patients, plasma levels of tyrosine measured hourly for six hours were elevated several times above levels found in euthyroid patients.³ In similar assays of oral tyrosine tolerance in hypothyroid subjects plasma levels after a tyrosine load were decreased below levels found in euthyroid subjects.The present investigation was intended to determine whether abnormal responses to orally administered loads of tyrosine are restricted to patients with . . .