Parenteral Plasma Protein Maintains Nitrogen Equilibrium Over Long Periods

Abstract

The main thesis of this paper is the "dynamic equilibrium" between body protein and plasma protein. A steady state or balance exists between the body protein stores, protein wear and tear, and protein production. Protein production includes the plasma proteins which probably represent the largest fraction of new formed protein. Body protein reserve stores are largely intracellular. We believe the plasma proteins are the means of a fluid interchange between reserve stores and the organ cells in which protein is produced, modified, and utilized in the body economy. The term "protein pool" suggests this fluid exchange within the body.Earlier experiments in this laboratory showed that plasma protein as plasma as the sole source of protein given by vein could maintain nitrogen equilibrium for 2 to 4 weeks (3, 11, 13). The last report (3) showed evidence of some "intoxication" which developed in two of these experiments. An attempt to reproduce this "intoxication" in the experiments tabulated below was not successful, and we are inclined to explain the "intoxications" previously described. as due to contaminated plasma or vitamin deficiency or both. The experiments given below are quite satisfactory and diet deficiencies were guarded against. The plasma was handled with more complete asepsis so we conclude that "intoxication" as described (3) is not an inevitable part of the experiment when large volumes of dog plasma are givenparenterally.In several experiments in other series at various intervals the dog's circulating plasma was fractionated and various elements estimated after the parenteral injection of plasma had been started--e.g., fibrinogen, globulins, albumins using coagulation, chemical methods, and electrophoretic technique. No uniform deviation from the normal plasma protein pattern was observed. Depleted dogs have a tendency to show some increase in globulins at the expense of albumins. It seems to us that the behavior offibrinogen is a very good illustration of the fact that long continued plasma given over months does not modify significantly the level of any plasma protein in the circulation. Fibrinogen is a very special protein used in the body for the production of blood clots. Yet obviously it is used in the body economy presumably within ceils to supply special cell needs (other than coagulation) since otherwise the fibrinogen

Plasma Protein Turnover and Tissue Exchange

“…This contained su-crose, lard, bone ash, salts, and vitamins (8), and the protein additions supplied from 3 to 30 per cent of the total calories. Table I summarizes the experimental conditions prevailing during the 7 day period after C 14 labeling in the 16 dogs given tagged plasma proteins intravenously.…”

Metabolic Studies on Protein-Depleted Patients Receiving a Large Part of Their Nitrogen Intake From Human Serum Albumin Administered Intravenously 12

“…Moreover, the significance of the positive nitrogen balance should be determined in the light of the following facts. There is abundant evidence that plasma proteins will pass certain membranous barriers (27,28). Albumin The mode, extent and determining factors of utilization of parenterally administered plasma protein has been of considerable interest both to us and to other investigators.…”

“…Whipple and his associates (28) have postulated "fluid interchange between the reserve stores and organ cells in which the protein is produced, modified and utilized in the body economy." Such a give and take might be accomplished without breaking the protein into its constituent amino acids.…”

Metabolic and Cardiovascular Studies of Prolonged Intravenous Administration of Human Serum Albumin

“…Subject D. F. in the last days of Experiment I was also in equilibrium. In the 60-and 90-day infusion studies of Terry and associates (4) There were many signs of albumin accumulation, in addition to that in the plasma. The peripheral lymph albumin concentration was 3.9 gm %o in Experiment IV; in Experiment III, it was 4.6 gm %o, with a control determination 3.2 gm %o made nine months after the experiment.…”