Albumin synthesis and nitrogen balance in postoperative patients

In a continuing prospective randomized study in a series of patients in the postoperative state, the rate of albumin synthesis was measured using the ¹⁴C carbonate technique. The majority of the patients studied were subjected to partial or total colectomy, and each patient was randomized to receive a hypocaloric intravenous regimen consisting of 3.5% amino acids (essential and nonessential) or 3.5% amino acids with 2.5% glucose. A mean (± SEM) of 75.7 ± 2.7 gm/day of amino acids was given to the seven patients in the amino acid group. A mean of 74.0 ± 5.9 gm/day of amino acids and 52.8 ± 4.2 gm/day of glucose was infused in the group of five patients given amino acids with glucose. The albumin synthetic rate (mg/kg/day) measured on the fourth day after operation in the amino acid alone group was 233.9 ± 27.9 as compared to 204.1 ± 24.4 in the group given amino acids with glucose (P = NS). The urea synthesis rates (mg/kg/day) in the two groups were 334.2 ± 47.8 and 250.3 ± 27.5, respectively, and the net Kjeldahl nitrogen balances (grams per day) were -4.98 ± 1.92 and -2.68 ± 1.49, respectively. We conclude that infused amino acids promote the synthesis of albumin equally effectively in the presence or absence of a small amount of added glucose. Glucose may reduce slightly the pool of amino nitrogen available for albumin and urea synthesis by diverting some of the infused amino acids from protein synthesis by the liver to muscle.