Creatine and Guanidoacetic Acid Metabolism in Pituitary Disease.

Schrire (1937) found that patients with an acidophil tumour of the pituitary excreted creatine in the urine, and this was later confirmed (Cumings, 1944). It was also shown in the latter paper that the fasting blood creatine was raised above the normal in acromegaly, and the results of a creatine tolerance test were given in five cases of pituitary disorders. The cause of the creatinaemia and creatinuria in acromegaly is obscure, but it had been shown previously that the urine excretion of creatine paralleled the height of the blood creatine provided that a level higher than 0.6 mg./100 ml. had been obtained. Guanidoacetic acid has been shown to be a precursor of creatine (Borsook and Dubnoff, 1940; 1941) and its estimation in pituitary disorders does not appear to have been recorded previously. This paper records a large series of patients with pituitary disorders, together with a few cases of thyrotoxicosis, in whom creatine and guanidoacetic acid studies have been made.