Blood Plasma Protein Production as Influenced by Amino Acids

Abstract

When blood plasma proteins are depleted by bleeding with return of the washed red blood cells (plasmapheresis) it is possible to bring dogs to a steady state of hypoproteinemia and a uniform plasma protein production on a basal low protein diet. These dogs are clinically normal. By the introduction of variables into their standardized existence insight into the formation of plasma proteins can be obtained. The liver basal diet maintains health in such hypoproteinemic dogs during periods as long as a year. 17 to 27 per cent of its protein content (entirely liver protein) is presumably converted into plasma protein. Gelatin alone added to the liver basal diet causes very little if any extra plasma protein production. The addition to gelatin of cystine, or tyrosine, or tryptophane, or of both tyrosine and tryptophane has little or no effect on its potency for plasma protein production. When gelatin is supplemented by cystine and either tryptophane or tyrosine, 25 to 40 per cent of the protein content of the combination is converted into plasma protein—an efficiency equaling that of any protein hitherto tested. Preliminary experiments indicate that methionine cannot substitute for cystine nor can phenylalanine substitute for tyrosine in the efficient combination of gelatin plus cystine plus tyrosine. Laked red blood cells given by vein afford little or no material for plasma protein formation. When the reserve stores of plasma protein building material are exhausted the dog can form little if any plasma protein during protein-free diet periods.

Blood Plasma Protein Production as Influenced by Various Degrees of Hypoproteinemia and by Amino Acids

“…The data presented in Tables 1 and 1-a, 2 and 2-a, are all obtained from one continuous 16-week experiment in a dog, 36-196, additionally valuable because of the similar experiments previously performed with its excellent cooperation (6,4). In Tables 1 and 1-a the data are given as the totals or averages of those obtained on the individual days of the consecutive weekly periods.…”

“…Tables 2 and 2-a present another experiment in the search for the specific construction materials in plasma protein synthesis. In our previous experiments (6,4) amino acids and incomplete proteins plus amino acids have been added to already adequate basal diets. In periods 14 and 15 gelatin, 20 gm.…”

“…1 and -a, 2 and 2-a). An adult female beagle hound used in similar experiments previously (6,4) ; bone ash 10 gm. When raw pork liver, 50 gm., was added in period 3 the cane sugar was reduced to 75 gm.…”

“…Experimental History.-Dog 36-196 (Tables 1 and -a, 2 and 2-a). An adult female beagle hound used in similar experiments previously (6,4) was in good condition after an interval of 12 weeks on a diet of hospital table scraps. The low protein diet contained only that protein present in the vitamin supplements, about 2 gm.…”

Amino Acids and Hemoglobin Production in Anemia

“…It is probable that asparagine in the intestine would react like aspartic acid. The sulfur containing amino acids (Table 5) are of particular interest because cystine is of prime importance in the regeneration of plasma protein in dogs (12). It is noted in Table 5 that cystine does give a substantial response--regeneration of 25 gin.…”