CREATINE-CREATININE METABOLISM AND THE HORMONES III. EFFECT OF PARENTERAL INJECTION OF CREATINE AND CREATININE WITH THE SEX HORMONES UPON CREATINE CREATININE EXCRETION IN NORMAL ANIMALS

ARECENT TEXT on biochemistry states that creatinine is a useless waste product and when ingested most of it is excreted into the urine. It further states that about one third of the body creatine is changed into creatinine and that the sex hormones are involved in this process (I). These views have long been accepted in the field of creatine creatinine metabolism and are derived chiefly from the fact that women and children are known to excrete some creatine while men usually do not. The sex hormones, however, do not effect the change of creatine into creatinine, even if creatine were transformed into creatinine. This is shown by the fact that almost as much creatinine is excreted in women as compared to men in 24-hour periods. We have shown that the so called constancy in creatinine elimination in both sexes is not due to body weight or muscle weight but to a uniform protein.