Creatinin Excretion in Women: Clinical Significance in Obesity

The daily excretion of creatinin on a meat-free diet is constant for each individual and is un-influenced by many external factors (1, 2). Since creatinin originates from endogenous sources, the determination of its excretion values has been advocated as a measure of the active protoplasmic mass in the body. Shaffer believed it to be derived from some special process of normal metabolism taking place largely, if not entirely, in the muscles (3). Recent studies which confirm this view show muscle creatin as the source (4–7), the total being related to the 24-hour urine creatinin output (8, 9). Creatinin excretion, therefore, affords an index of the proto-plasmic activity of the muscles and, indirectly, of the total muscle mass assuming this activity to be basal and constant. Folin first observed diminished excretion of creatinin at a given weight in the obese individual, suggesting the validity of the creatinin coefficient (3) as an index of nutrition.