Protein katabolism and oxygen consumption during starvation in infants, young adults and old men.

In their work on the partition of nitrogen in the urine of newborn breast-fed infants Barlow & McCance (1948) found that the total nitrogen excreted during the first 48 h of life was of the order of 30 mg/kg body-weight/zq h. During this time the breast-fed infant obtains very little food and fluid and is in a state of physiological hydropenia and of almost complete starvation. Barlow & McCance pointed out that Cathcart’s (1907) and Benedict’s (1915) work had shown that the starving adult, with an unrestricted water intake, excreted about 140 mg N/kg body-weightjzq h. Although this was a large difference they did not claim that it represented a difference in the nitrogen katabolized because it was known from previous work (McCance & Widdowson, 1947) that there was usually some retention of nitrogen over the first 2 days of life, and this had not been measured. A re-examination of this evidence in 1949 suggested that the nitrogen katabolized by infants per kg body-weight in the first 48 h of life really was smaller than that katabolized by fasting adults. This was felt to be curious since Benedict & Talbot (1915) had found that the calorie output of resting infants was 48 Cal./kg/zq h, whereas that of adults was only 23 Cal./kg/zq h. Little help in the resolution of this difficulty could be obtained from the literature. Schlossmann & Murschhauser (1914) appeared to have been two of the few, if not the only, investigators to have measured the nitrogen katabolism and the calorie expenditure of the same starving baby. In