Urinary Excretion of 3‐Methylhistidine in Patients Receiving Parenteral Nutrition

Abstract

In an attempt to investigate the kinetics of the muscle protein during parenteral nutrition (PN) and surgical stress, the urinary output of 3-methylhistidine (3-Mehis) was measured in patients receiving PN, then the validity of urinary 3-Mehis excretion as an index for the patient's status of protein nutrition was examined. The amounts of 3-Mehis excreted in 24 hr urine in the 19 healthy males and 10 healthy females were 74.8 +/- 17.1 mg/day and 46.3 +/- 12.4 mg/day, respectively. The changes of daily urinary 3-Mehis output in 6 cases receiving PN for more than 4 weeks were also examined. The average urinary 3-Mehis excretion increased gradually during the course of PN, and by the third week was nearly twice as high as the level before PN. In a further study the influence of surgery upon the urinary excretion of 3-Mehis was examined in 9 patients. Finally, a comparison was made of the nutritional status before and 4 wks after PN in the 6 patients without surgical stress. Urinary 3-Mehis was found to be a good index of both the status of protein nutrition and the fluctuation of muscle protein catabolism.