Ten Amino Acids Essential for Plasma Protein Production Effective Orally or Intravenously

Abstract

When blood plasma proteins are depleted by bleeding with return of the washed red cells (plasmapheresis) it is possible to bring dogs to a steady state of hypoproteinemia and a constant level of plasma protein production if the diet protein intake is controlled and limited. Such dogs are outwardly normal but have a lowered resistance to infection and to certain intoxications. When the protein intake of such dogs is completely replaced by the growth mixture (Rose) of crystalline amino acids, plasma protein production is excellent, weight and nitrogen balance are maintained. This growth mixture consists of ten amino acids, threonine, valine, leucine, isoleucine, tryptophane, lysine, phenylalanine, methionine, histidine, arginine, and is as effective as most diet proteins in plasma protein production. The above amino acid mixture in aqueous solution may be given by vein with equally good plasma protein production and no apparent clinical disturbance even when given rapidly. Cystine may replace methionine in the above mixture with equally good plasma protein production for 7 to 10 days but at the expense of the body tissues, that is, with weight loss and a negative nitrogen balance. The addition of cystine to the protein-free, otherwise adequate diet may result in the production of considerable new plasma protein during a period as long as 1 week (cystine effect). This reaction may depend upon the amino acid constitution of the preceding diet protein in that it occurred following a liver feeding but did not occur after pancreas feeding. Arginine is required in the diet of the protein depleted dog for fabrication of plasma protein. It is apparently not needed for nitrogen balance for as long as 1 or 2 weeks. The omission of either threonine or valine from the growth mixture is quickly followed by a sharp decline in plasma protein formation and by a negative nitrogen balance. When histidine, arginine, and most of the lysine are omitted from the growth mixture, nitrogen balance and weight may be maintained for as long as 1 week but plasma protein production falls off markedly. The findings indicate that the growth mixture of amino acids should be a valuable addition to transfusion and infusion therapy in disease states associated with deficient nitrogen intake or tissue injury and accelerated nitrogen loss, including shock, burns, and major operative procedures.

Amino Acid Mixtures Effective Parenterally for Long Continued Plasma Protein Production. Casein Digests Compared

“…These experiments follow the same general pattern of those in previous reports (11,12). A dog is standardized for tests of plasma protein production by a process of body protein and plasma protein depletion.…”

“…Certainly the low urinary nitrogen levels of such periods as 8, 9, 10, 16, and 17 suggest very good utilization of the injected amino acids. Data previously presented and discussed (11) suggest that 4.5 gm. is the approximate urinary nitrogen output of the minimal nitrogen metabolism of this dog.…”

“…In a previous report (11) it was found that good plasma protein regeneration was obtained from feeding or injecting the ten amino acids determined by Rose (21) to be essential for the growth of rats. Further tests have now been made of various mixtures of these ten acids and of non-essential amino acids.…”

Human Skeletal Muscle Protein Metabolism Responses to Amino Acid Nutrition

“…He showed that sugar-fed animals could produce plasma proteins at the cost of tissue and, conversely, could maintain muscle mass, good health, and sustained nitrogen equilibrium when transfused only with plasma proteins (1). Within a decade it was shown that the sole protein derivatives that are both essential and sufficient to maintain health and nitrogen equilibrium were the amino acids (AAs) 8 threonine, valine, leucine, isoleucine, lysine, tryptophan, phenylalanine, methionine, and histidine-the "essential" AAs (EAAs) (2). By the 1970s, in vitro work in skeletal muscle preparations provided evidence that the role of AAs may not simply be as substrates for protein synthesis, with each having the potential to limit synthesis dependent on availability and the relative contribution of tissues (3).…”

Anemia, Hypoproteinemia, and Cataracts in Swine Fed Casein Hydrolysate or Zein. Comparison With Pyridoxine-Deficiency Anemia 1

“…Evidence from experiments in dogs indicates that tryptophane plays a role in the formation of plasma proteins (6) and hemoglobin (3,4,7). In tryptophane deficiency produced experimentally for periods of 2 to 5 weeks in human subjects, one of us (M. M. W.) working with the first mentioned workers (1) was unable to demonstrate significant alterations in the red cells.…”