Studies of Serum Creatine Tolerance. I. Findings in Normal Males and in Hyperthyroidism 12

Abstract

In 1929, Palmer, Carson, and Sloan (1) reported that treatment of exophthalmic goiter with Lugol's solution reduced or abolished the associated creatinuria. More recently Richardson and Shorr (2, 3) and Thorn (4) have shown that hyperthyroid individuals excrete a larger proportion of a given dose of creatine than do comparable normal individuals, and that this "reduced tolerance" is partially or totally reversible by effective therapy. The development by one of us of a practical method for the determination of creatine in serum (5) led Tierney and J. P. Peters to investigate the effects of exogenous creatine on serum levels in normal humans and in thyroid disease (6). Their findings revealed that the increased creatinuria reflected increased serum concentrations, and that the "critical" serum level for the excretion of creatine was approximately 0.6 mg. %b.Because of the differences in the mode of excretion of creatine by adult males and females, we have undertaken a study of serum creatine tolerances of men with hyperthyroidism and of others with clinical conditions simulating Graves' disease in order to further define the nature of sex differences in creatine metabolism. It also seemed important to determine whether the increased tolerance noted by Tierney and Peters in one male (6) was a characteristic of this disease in men.