[Phosphocreatine metabolic indices during increased and decreased energy expenditures in man]

Changes in phosphocreatine metabolism (creatinine excretion in the urine and arginine content in plasma--one of the amino acids that are involved in creatine synthesis) were studied in 40 male test subjects who performed increased or decreased work and consumed standard protein food. It was shown that there was a correlation between creatinine excretion in the urine and the content of arginine in plasma, on the one hand, and the amount of nitrogen consumed, on the other. It was also found that at increased or decreased energy expenditures creatinine excretion and arginine content elevated. These data are indicative of changes in phosphocreatine metabolism in response to the environmental effects.