In a previous report1 we discussed various factors influencing the ability of patients with progressive muscular dystrophy to retain ingested creatine. In the series of twenty cases investigated the creatine tolerance was impaired so that a large part of an administered dose of creatine was excreted unchanged in the urine. The defect in the ability to retain exogenous creatine varied with the degree of muscular disability. In adult patients in the early stages of the disease as much as 82 per cent of the ingested creatine was retained, whereas in patients showing advanced muscular wasting the creatine tolerance was impaired to the extent that all the ingested dose of creatine was excreted unchanged.
The amount of creatine usually administered in performing the creatine tolerance tests in our studies was 1.32 Gm. However, other workers have used widely different amounts. Thus, Boothby and his associates2 gave 1 Gm.; one