Conversion of plasma protein to tissue protein without evidence of protein breakdown; results of giving plasma protein labeled with carbon 14 parenterally to dogs

Labeled plasma proteins obtained from donor dogs, previously fed ε-C¹⁴-dl-lysine, have been given intravenously to recipient dogs. The disappearance of labeled globulin from the plasma at a rate considerably faster than albumin has been confirmed. Evidence suggesting that the mass of protein in solution in the extravascular, extracellular fluid is approximately equal to the plasma proteins in circulation has been derived from a study of the dilution of labeled plasma protein by repeated injections of non-labeled plasma protein. In a period of 7 days the transfer of C¹⁴ from plasma to tissue proteins amounted to between 30 and 40 per cent of the activity in the labeled plasma protein injected intravenously. The conversion was accompanied by a very small loss of activity in the urine and expired air and the activity remained in the lysine residue of the liver and probably of other tissues. The data presented favor the view that plasma proteins are utilized in the body economy after partial catabolism within the cell area and provide no evidence of complete breakdown to the amino acid level.     

Inflammation and protein metabolism studies of carbon-14-labeled proteins in dogs with sterile abscesses

Carbon-14-labeled plasma proteins given by mouth to dogs with sterile abscesses undergo decreased absorption, presumably owing to impaired digestion of protein. The turnover of plasma albumin is greatly accelerated but the globulins, excluding fibrinogen, show little change during the acute stage of the sterile inflammation. Fibrinogen shows very rapid production and utilization during acute inflammation. Large amounts of C¹⁴ are incorporated in fibrinogen within a few hours after ingestion of the labeled material. The labeled fibrinogen largely disappears within 2 to 4 days after its production. The appearance of C¹⁴ in new red cells from labeled protein or amino acid sources is reduced by inflammation—evidence of impaired synthesis. The pus of the sterile abscess contains a good deal of C¹⁴ activity which at times is as much as that found in the liver. Pus cell C¹⁴ activity per milliliter is similar after injection of labeled plasma and ingestion of labeled plasma or lysine. However, the pus cell fraction contains 3 to 4 times more C¹⁴ activity per milliliter than does the supernatant fluid when the isotope is fed. In the supernatant fluid the activity is all within precipitable protein, much of which is probably derived from the blood plasma. In spite of increased loss of C¹⁴ as CO₂ in the expired air and in the pus, there is evidence of conservation of protein-building materials for maintenance of new plasma proteins and tissue proteins in the more active organs (e.g. liver)—a shift of protein C¹⁴ from the less active tissues (muscle and skin).     

NUTRITIONAL EDEMA IN THE DOG : I. DEVELOPMENT OF HYPOPROTEINEMIA ON A DIET DEFICIENT IN PROTEIN

1. The concentration of protein in the serum and plasma of normal dogs is given. Analyses of serum from 38 animals yielded the following averages and standard deviations, (a) for albumin: 3.26 ± 0.48 gm. per cent, (b) for globulin: 2.72 ± 0.76 gm. per cent, and (c) for total protein: 5.98 ± 0.67 gm. per cent. Analyses of plasma from 19 animals showed, (a) for albumin: 3.38 ± 0.38 gm. per cent, (b) for globulin: 2.98 ± 0.55 gm. per cent, and (c) for total protein: 6.36 ± 0.71 gm. per cent. 2. A diet for dogs is described, the feeding of which results in a progressive decline in the concentration of protein in the serum. A composite curve constructed from the findings with 21 animals discloses a rapid initial fall and a slower subsequent decrease in albumin and total protein and an approximately constant level for globulin. The course of the globulin curve was subject to wide variation in separate experiments, both increases and decreases being recorded. 3. With five dogs the nitrogen balance was followed through a total of 42 metabolism periods of approximately 7 days each. The average daily loss of nitrogen was 1.15 gm. Approximate calculations disclose that only 3 or 4 per cent of the nitrogen eliminated is accounted for by the decline in circulating protein, the remainder being represented by loss from the tissues. 4. An episode is described with one dog when, during a period of self-imposed fasting, the serum albumin regenerated to a normal level, apparently at the expense of catabolized tissue protein. 5. The course of serum proteins is described during the recovery which follows interruption of the low protein diet and return to a regime of adequate feeding. 6. A discussion is given of the relationship between tissue proteins and plasma proteins. The data permit one to entertain the hope that a way will be found for stimulating an internal readjustment to provide temporary relief from hypoproteinemia, a way which will depend upon the potential ability of the tissues to provide sufficient protein for the needs of the plasma.     

Plasma protein labeled with lysine-epsilon-C14; its oral feeding and related protein metabolism in the dog

The metabolism of homologous plasma proteins, labeled with lysine-ε-C¹⁴, after oral administration to dogs has been investigated. The speed of the various processes involved is indicated by the maximum rate of C¹⁴ O₂ excretion which is attained within 1 to 4 hours, the prompt appearance of protein activity in the plasma and disappearance of non-protein activity from it, both virtually complete in 7 to 10 hours, as well as the rapid incorporation of a large percentage of the fed-C¹⁴ into tissues. There are no essential differences between the behavior of labeled plasma and that of an amino acid digest containing ε-C¹⁴ labeled lysine when these two materials are given orally. At the end of 48 hours after labeled plasma feeding, a CO₂ elimination of 16 to 28 per cent of the fed C¹⁴ is noted. In contrast, after 48 hours following labeled plasma by vein, a CO₂ elimination of only 2.5 per cent is recorded—almost a 10 to 1 ratio. We believe this, together with the data concerning plasma and tissue protein activity, represents a significant difference in the metabolic process. The evidence favors a complete breakdown of plasma protein to the amino acid level when given orally but not when given by vein.     

STUDIES ON HYPOALBUMINEMIA PRODUCED BY PROTEIN-DEFICIENT DIETS : I. HYPOALBUMINEMIA AS A QUANTITATIVE MEASURE OF TISSUE PROTEIN DEPLETION

In five dogs placed on a protein-poor diet for 3 weeks, the decline in total circulating plasma albumin was a small (3 per cent) but relatively constant part of the total nitrogen lost. These data together with observations on dogs by others indicate that there is a constant relationship or partition in the loss (or gain) between plasma albumin and total body protein induced by diet. Based on this relationship a formula is developed for estimating the degree of total tissue protein deficiency from the value of the serum albumin concentration alone. This formula would also apply to the replenishment of protein deficiencies of dietary origin and it indicates that for every gram of increase in serum albumin desired about 30 gm. must be retained for increases in other proteins of the body.     

BLOOD PLASMA PROTEIN REGENERATION AS INFLUENCED BY FASTING,INFECTION, AND DIET FACTORS : VARIABLE RESERVE STORES OF PLASMA PROTEIN BUILDING MATERIAL IN THE DOG

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 uniform plasma protein production on a basal low protein diet. These dogs are clinically normal with normal appetite, no anemia and normal nitrogen metabolism. These dogs become test subjects by which various factors relating to plasma protein production may be tested. The normal dog (10 to 13 kg.) has a substantial reserve store of plasma protein building material (10 to 60+ gm.) which requires 2 to 6 weeks plasmapheresis for its complete removal. After this period the dog will produce uniform amounts of plasma protein each week on a fixed basal diet. Dogs previously depleted by plasmapheresis and then permitted to return to normal during a long rest period of many weeks, may show much higher reserve stores of protein building material in subsequent periods of plasma depletion (see Table 1). Under uniform conditions of low protein diet intake when plasmapheresis is discontinued for 2 weeks the plasma protein building material is stored quantitatively in the body and can subsequently be recovered (Table 4) in the next 2 to 3 weeks of plasmapheresis. Given complete depletion of plasma protein building reserve stores the dog can produce very little (2± gm. per week) plasma protein on a protein-free diet. This may be related to the wear and tear of body protein and conservation of these split products. Abscesses produced in a depleted dog during a fast may cause some excess production of plasma protein which is probably related to products of tissue destruction conserved for protein anabolism. Gelatin alone added to the basal diet causes very little plasma protein production but when supplemented by tryptophane gives a large protein output, while tryptophane alone is inert.     

MAXIMAL HEMOGLOBIN AND PLASMA PROTEIN PRODUCTION UNDER THE STIMULUS OF DEPLETION

The maximal output ceiling for hemoglobin in anemia due to blood loss is about 60 gm. per week—the dog receiving a rich protein diet plus high iron intake. Ferrous and ferric salts are equally effective. Iron intravenously plus a rich protein diet may push this level up to 90 to 100 gm. per week. Evidently iron absorption is a limiting factor. Maximal output for hemoglobin plus plasma protein in doubly depleted dogs may reach 120 to 130 gm. per week and using intravenous iron may reach 140 to 160 gm. per week. Maximal output for plasma protein alone in hypoproteinemia due to plasmapheresis reaches 60 to 70 gm. per week but this is not the true ceiling. Technically we cannot remove the new plasma protein as fast as it is formed and the hypoproteinemia is not maintained in the face of a rich protein diet intake. Furthermore the evidence points to the protein circulating pool contributing to the accretion of tissue protein in such dogs with a strong positive nitrogen balance and weight gain. Maximal figures for hemoglobin production in anemia run close to 1 gm. hemoglobin per kilo per day. Maximal figures for new hemoglobin plus plasma protein production in anemia and hypoproteinemia using iron given intravenously, may reach 1.5 gm. blood protein per kilo per day. The actual maximal plasma protein production equals about 1 gm. per kilo per day but the true production ceiling cannot be reached by this technique, for reasons given above.     

LOW PROTEIN DIET AUGMENTS HYPERPROTEINEMIA PRODUCED BY REPEATED INJECTIONS OF HOMOLOGOUS PLASMA : EVIDENCE FOR A DYNAMIC EQUILIBRIUM BETWEEN FOOD,PLASMA, AND TISSUE PROTEINS

1. In 4 dogs maintained on a high protein diet (lean meat) repeated intravenous injections of plasma obtained from healthy donor dogs (18 to 24 injections during the course of 3 to 4 weeks, totalling 1595 to 4355 cc.—averaging 1800 cc. when figured on thc basis of a 5 kg. dog) resulted in a mean increase in the plasma protein concentration of 20 per cent (from 7.1 per cent to 8.5 per cent). 2. In 7 dogs maintained on a low protein diet (only 7 per cent of total caloric value derived from protein) almost identical injections of donor''s plasma caused an average increase in the plasma protein concentration of 40 per cent (from 6.7 per cent to 9.4 per cent). 3. The albumin:globulin ratio in the group on the low protein diet showed an average fall of 30 per cent (from 1.4 to 0.9) while in the group on the high protein diet the change in this ratio was insignificant (from 1.3 to 1.2). 4. In all dogs in both groups there was a consistent fall in the hematocrit value of about 15 to 20 per cent (from 49 to 40, or 18 per cent) which can be explained in part at least by the increase in plasma volume of about 15 per cent. 5. There were no significant changes in body weight or in plasma N.P.N.     

The circulation of ascitic fluid; interchange of plasma and ascitic fluid protein as studied by means of C14-labeled lysine in dogs with constriction of the vena cava

After plasma containing labeled plasma protein has been given intraperitoneally to dogs with experimental ascites a steady and rather rapid movement takes place of the labeled protein into the circulating blood. When plasma containing labeled plasma protein has been injected intravenously into the ascitic dog the labeled protein steadily disappears from the circulating blood and appears promptly and steadily in the ascitic fluid. The period of complete exchange or turnover in either instance is measured in days (2 to 7), but many factors enter in and make for variation. Lysine labeled with radio carbon is incorporated into the plasma proteins by feeding the donor dog. These experiments emphasize the ready exchange of proteins in the plasma with those in the ascitic pool and vice versa. This exchange may be termed circulation of ascitic protein.     

The phospholipid composition of human serum lipoprotein fractions separated by electrophoresis on agarose gel. Demonstration of a fraction with high lysolecithin content

The theory that intact collagen molecules (or large segments thereof) may be used in restructured collagen was tested by a double isotope-labelling technique. A ³H:¹⁴C isotope ratio was established in the mature connective tissue of ten female Wistar rats by an intraperitoneal injection of L-[³H]proline and [¹⁴C]glycine. Twentyeight days after the injection, granulation tissue was induced by subcutaneous dorsal implantation of ten hollow steel-mesh cylinders per animal. The cylinders were then removed along with skin samples at intervals over a 21-day period. During this time three animals received a diet supplemented with 15% unlabelled L-proline and three received a diet supplemented with 15% unlabelled glycine. If the granulation tissue consisted of reutilized collagen the isotope ratio would remain unchanged regardless of the diet. If the collagen came from de novo synthesis the isotope ratio would change because the ³H and ¹⁴C must pass through separate pools. Our results show that a large proportion of the radioactivity previously identified as arising from reutilized labelled collagen is actually the result of local protein catabolism and recycling of labelled amino acids for de novo synthesis. These experiments do not conclusively disprove the collagen reutilization theory but indicate the need for further investigations using a labelled compound that cannot be recycled.     

BLOOD PLASMA PROTEIN REGENERATION CONTROLLED BY DIET : EFFECTS OF PLANT PROTEINS COMPARED WITH ANIMAL PROTEINS THE INFLUENCE OF FASTING AND INFECTION

When blood plasma proteins are depleted by bleeding, with return of washed red cells (plasmapheresis), it is possible to bring the dog to a steady state of low plasma protein in the circulation and a uniform plasma protein production on a basal diet. These dogs become test subjects by which the potency of various diet factors for plasma protein regeneration can be measured. Plant and grain proteins are quite well utilized to form new plasma protein in these test dogs but soy bean meal probably should be rated at the head of this list. It is utilized with unexpected promptness and favors the production of albumin in contrast to other plant proteins which distinctly favor globulin production. Long plasmapheresis periods on basal rations rich in grain proteins lower the resistance of these animals to infection. Spleen, brain, and stomach when fed with the basal diet in these test dogs show less favorable potency ratios—10.2, 11.8, and 13.6 respectively. This means the grams of tissue protein which must be fed to produce 1 gm. of new plasma protein. Fasting periods indicate that the dog can contribute only 4 to 6 gm. of plasma protein each week—an insignificant contribution presumably derived from the host''s tissue proteins. Infection and intoxication disturb the plasma protein production of these standardized dogs and may reduce the output of plasma proteins to very low levels in spite of considerable food intake. There may be a very sharp drop in the plasma protein level during the first day of intoxication (Dog 33-324). Some of these observations may be of value in a study of clinical conditions associated with hypoproteinemia.     

BLOOD PLASMA PROTEIN PRODUCTION AS INFLUENCED BY AMINO ACIDS : CYSTINE EMERGES AS A KEY AMINO ACID UNDER FIXED CONDITIONS

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 REGENERATION CONTROLLED BY DIET : I. LIVER AND CASEIN AS POTENT DIET FACTORS

When blood plasma proteins are depleted by bleeding and return of the washed red cells (plasmapheresis) the regeneration of new plasma proteins can be controlled at will by diet. The amount and character of protein intake is all important. Liver protein and casein are efficient proteins to promote rapid regeneration of plasma proteins but some vegetable proteins are also efficient. The blood plasma proteins are reduced by plasmapheresis close to the edema level (3.5–4.0 per cent) and kept at this level by suitable exchanges almost daily. The amount of plasma protein removed is credited to the given diet period. A basal ration is used which is poor in vegetable protein (potato) and contains no animal protein. The dog on this ration can be kept in nitrogen balance but can produce only about 2 gm. plasma protein per kilo body weight per week. With liver or casein feeding this production can be increased three- or fourfold. A reserve of protein building material can be demonstrated in the normal dog when its plasma proteins are depleted. In the first 3 weeks of depletion this reserve in excess of the final basal output may amount to 3–20 gm. protein. This may be stored at least in part in the liver. As much as 50 per cent of this reserve may be albumin or albumin producing material. A reversal of the albumin-globulin ratio may be observed on the basal diet alone. The reversal will always follow plasmapheresis with the dog on the basal diet and the total plasma protein output will consist approximately of 2 parts globulin and 1 part albumin. Liver diet will raise the production and output of albumin and bring the ratio back toward normal. Albumin production may actually exceed the globulin output during liver diet periods. The change is less conspicuous with casein but in the same direction.     

BLOOD PLASMA PROTEIN PRODUCTION AS INFLUENCED BY VARIOUS DEGREES OF HYPOPROTEINEMIA AND BY AMINO ACIDS

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 but their resistance to infection is distinctly below normal. Introduction of variables into this standardized existence gives information relative to plasma protein production. Plasma protein production under these conditions with a plasma protein concentration of 3.5 to 4.2 gm. per cent is relatively constant. As the plasma protein concentration rises the plasma protein removed falls rapidly (Table 1). At 4.6 gm. per cent the protein removed is less than 50 per cent of the amount removed at a plasma protein level of 4.0 gm. per cent. Cystine appears to be an important amino acid for plasma protein formation. This shows in Table 2 and is supported by data coming from published experiments. These experiments related to the factors which control plasma protein production bear on the problems of shock, hemorrhage, and protein wastage and their treatment by plasma injections which hold the attention of surgeons and physiologists at the moment. Again we would emphasize the fluidity of body protein including plasma protein—an ebb and flow between protein depots and plasma protein—a "dynamic equilibrium" of body protein. A discussion of the passage of large protein molecules through cell borders is submitted.     

Anemia plus hypoproteinemia in dogs; various proteins in diet show various patterns in blood protein production; beef muscle,. egg,lactalbumin, fibrin,viscera, and supplements

Dogs with sustained anemia plus hypoproteinemia due to bleeding and a continuing low protein or protein-free diet containing abundant iron have been used in the present work to test food proteins and supplements as to their See PDF for Structure capacity to produce new hemoglobin and plasma proteins. The reserve stores of blood protein-producing materials are thus largely depleted in such animals and sustained levels of 6 to 8 gm. per cent hemoglobin and 4 to 5 gm. per cent plasma protein can be maintained for considerable periods of time. The stimulus of double depletion drives the body to use all protein building materials with the utmost conservation. This represents a severe biological test for food and body proteins and its assay value must have significance. Measured by this biological test in these experiments, casein stands well up among the best food proteins. The ratio of plasma protein to hemoglobin is about 40 to 50 per cent, which emphasizes the fact that these dogs produce on most diets about 2 gm. hemoglobin to 1 gm. plasma protein. The reason for this preference for hemoglobin production is obscure. The mass of circulating hemoglobin is greater even in this degree of anemia and the life cycle of hemoglobin is much longer than that of the plasma protein. Egg protein, egg albumin, and lactalbumin all favor the production of more plasma protein and less hemoglobin as compared with casein. The plasma protein to hemoglobin ratio is increased, sometimes above 100 per cent. Supplements to the above proteins of casein digests or several amino acids may return the response toward that which is standard for casein. Histidine as a supplement to egg protein increases the total blood protein output and brings the ratio of plasma protein to hemoglobin toward that of casein. Beef muscle goes to the other extreme and favors new hemoglobin production up to 4 gm. hemoglobin to 1 gm. plasma protein—a ratio of 25 per cent. The total amounts of new blood proteins are high. Lactalbumin as compared with casein shows a lower total blood protein output and a plasma protein to hemoglobin ratio of 70 to 90 per cent. Amino acid supplements are less effective. See PDF for Structure Fibrin is a good food protein in these experiments—much like casein. When fed over these 5 week periods it causes a sustained increase in blood fibrinogen. Folic acid in the doses given has no effect on the expected response to various diets. Peanut flour is a very poor diet for the production of new hemoglobin and plasma proteins. Small supplements of casein and beef show a significant response with improved output of blood proteins. Soy bean flour gives a poor response and wheat gluten a good response with adequate output of blood proteins. Visceral products show some variety. Beef heart is not as effective as beef muscle. Beef spleen, kidney, and pancreas give good responses but not up to casein. Pig stomach, beef brain, and calf thymus are below average. The plasma protein to hemoglobin ratio shows a narrow range (40 to 60 per cent) in experiments with visceral products.     

HEMOGLOBIN AND PLASMA PROTEIN : SIMULTANEOUS PRODUCTION DURING CONTINUED BLEEDING AS INFLUENCED BY AMINO ACIDS,PLASMA, HEMOGLOBIN,AND DIGESTS OF SERUM,HEMOGLOBIN, AND CASEIN

Given healthy dogs, fed abundant iron and protein-free or low protein diets, with sustained anemia due to bleeding, we can study the capacity of these animals to produce simultaneously new hemoglobin and plasma protein. The reserve stores of blood protein producing materials in this way are very largely depleted, and levels of 6 to 8 gm. per cent for hemoglobin and 4 to 5 gm. per cent for plasma protein can be maintained for considerable periods of time. These dogs are very susceptible to infection and to injury by many poisons. Under such conditions, these anemic and hypoproteinemic dogs will use very efficiently a variety of digests (serum, hemoglobin, and casein) and the growth mixture (Rose) of pure amino acids. Nitrogen balance is maintained and considerable new blood proteins are produced. Dog plasma by vein is used freely in these doubly depleted dogs to make new hemoglobin in abundance (Table 1). Serum digests by vein are well utilized to make new hemoglobin and plasma protein in the same dogs (Table 1). Serum digests by mouth are effectively used to make new blood proteins (Table 5). Dog or sheep hemoglobin given in large amounts intraperitoneally are remarkably well utilized to form hemoglobin and plasma protein (Table 6). It must be obvious that the globin of the hemoglobin is saved in these protein-depleted dogs and used to make large amounts of hemoglobin and plasma protein. Hemoglobin digests are also well utilized whether given by mouth (Table 7) or by vein (Table 8) and liberal amounts of plasma protein are manufactured from digests presumably ideally suited for hemoglobin production. Casein digests are well used (Table 8) and form as much new plasma protein as any material tested—even serum digests. Amino acid mixtures are of especial interest. The growth mixture of 10 amino acids (Rose) is well utilized by mouth or by vein and favors new hemoglobin production more than any material tested (Table 2). Cystine replacing methionine in the amino acid mixture increases the plasma protein—hemoglobin output ratio, that is it favors plasma protein production. Digests of various sorts and amino acid mixtures or combinations of digests and amino acid mixtures can be used rapidly and effectively to build new hemoglobin or plasma protein, to maintain nitrogen equilibrium, and to replete reserve protein stores. These experiments point to clinical problems. The unexplained preference given to hemoglobin production in these hypoproteinemic dogs is observed under all conditions, even when whole plasma or serum digests are given by vein. In general, 2 to 4 gm. of hemoglobin are formed for every gram of plasma protein. This all adds up to a remarkable fluidity in the use of plasma protein or hemoglobin which can contribute directly to the body protein pool from which are evolved, without waste of nitrogen, the needed proteins, whether hemoglobin, plasma protein, or tissue proteins.     

BLOOD PLASMA PROTEIN REGENERATION AS INFLUENCED BY INFECTION,DIGESTIVE DISTURBANCES,THYROID, AND FOOD PROTEINS : A DEFICIENCY STATE RELATED TO PROTEIN DEPLETION

When blood plasma proteins are depleted by bleeding, with return of washed red cells (plasmapheresis), it is possible to bring dogs to a steady state of low plasma protein in the circulation and a uniform plasma protein production on a basal diet. Such dogs become test subjects by which the effect of various factors on plasma protein regeneration can be measured. Dogs previously the subjects of plasmapheresis, during long rest periods appear to increase their stores of plasma protein building materials and their blood plasma protein concentrations above former normal levels. A sterile abscess (turpentine) induces a marked reduction in plasma protein regeneration in these test dogs consuming an ample basal diet. The sharp reduction during the initial 24 hours may in part reflect an extravasation of plasma protein into the injured tissue but there also appears to develop a true disturbance of the mechanism which produces plasma proteins. Digestive disturbances interfere seriously with plasma protein production. Whereas large quantities of live yeast upset digestion and form no plasma protein, autoclaved yeast is well utilized, having a potency ratio of 4.4. Amino acids have been tested inadequately. A mixture of cystine, glutamic acid, and glycine does seem to have a definite effect upon protein metabolism and plasma protein production. Iron, under the conditions of these experiments, does not influence the output of plasma proteins. Liver extract (parenteral) is also inert. The proteins of red blood cells when added to the diet are poorly utilized for plasma protein formation and show a potency ratio of only 10.1. Kidney protein added to the kidney basal diet shows a potency ratio of about 5 as compared with 4.6 for that basal diet. A digest of beef stomach and rice polishings shows a potency ratio of about 7.9. Dried powdered serum shows a potency ratio of 3.5, which is much less than fresh serum (2.6). Powdered thyroid fed in doses sufficient to accelerate body metabolism shows no distinct effect upon plasma protein production not attributable to the protein in the thyroid powder itself. Long periods (25 to 30 weeks) of plasma depletion and basal diet intake remove much protein from body fluids and tissues. Associated with this protein depletion the dog loses its appetite and may vomit some food. There is loss of hair, a tendency to skin ulceration, and a distinct lowering of resistance to infection. The plasma protein output may fall to fasting levels in spite of food intake sufficient to maintain weight. We believe this condition to be a deficiency state related to severe depletion of the essential protein matrix of the body cells.     

Influence of dietary protein on the anti-inflammatory and ulcerogenic effects and on the pharmacokinetics of phenylbutazone in rats.

Influence of dietary protein deficiency on the anti-inflammatory and ulcerogenic effects and on the kinetics of phenylbutazone was studied in male Sprague-Dawley rats fed ad libitum a 21% (control) or a 5% (low) protein diet for 3 weeks. A low protein diet fed to a decrease in body weight gain, plasma proteins, albumin, globulins, hepatic total and microsomal proteins and in cytochrome P-450. Phenylbutazone produced a greater ulcerogenic effect in rats fed a low protein diet than in control rats; its anti-inflammatory effect did not increase. Plasma t 1/2 of phenylbutazone was longer in protein-deficient rats than in control rats. Dietary protein deprivation led to a decrease in the plasma clearance and plasma protein binding of phenylbutazone but did not lead to a change in its bioavailability. No relationship between the severity of gastric ulceration and the concentration of phenylbutazone or oxyphenbutazone in the stomach tissue was found in any animal of the two groups. The increased susceptibility of protein-deficient rats to the ulcerogenic effect of phenylbutazone was reversible and was not observed when these animals were fed a control diet for 3 weeks. It is concluded that a dietary protein deficiency increases the ulcerogenic toxicity of phenylbutazone relative to its useful anti-inflammatory effects.     

Splanchnic Secretion Rates of Plasma Triglycerides and Total and Splanchnic Turnover of Plasma Free Fatty Acids in Men with Normo- and Hypertriglyceridaemia

Abstract. Plasma triglyceride (TG) “turnover rates” were estimated in the fasting state in three different ways: splanchnic chemical TG secretion, splanchnic isotope TG secretion and plasma TG clearance. Forty-two men with a wide range of fasting plasma TG concentrations, from 0.53 to 16.50 mmol/l were investigated. A constant intravenous infusion of albumin-bound ³H-labelled palmitate was given and blood was simultaneously sampled from the hepatic vein and an artery for determination of hepatic venous-arterial differences of labelled and unlabelled plasma TG. In addition total and splanchnic turnovers of plasma FFA were measured. Similar values were obtained for plasma TG “turnover rate” by the splanchnic chemical TG secretion and the plasma TG clearance method. The values for these two methods varied between 3 and 74 μmol/min. and m² body surface area, except for two cases who had considerably higher values. The splanchnic isotope TG secretion method gave lower values varying from 1 to 34 μmol/min. and m² body surface area. This method probably measures only that fraction of the splanchnic TG secretion which is derived from plasma FFA. No correlations were found among normotriglyceridaemic subjects between plasma total TG or VLDL-TG concentrations and plasma TG “turnover rates” measured by any of the three methods. For patients with hypertriglyceridaemia significant positive correlations were found between plasma VLDL-TG concentrations and plasma “turnover rates”. The “fractional turnover rate” decreased with increasing TG levels in an apparently hyperbolic fashion. The results suggest an impaired plasma TG removal capacity in patients with hypertriglyceridaemia. In 7 out of 14 patients the plasma TG “turnover rates” were in the upper part of the normal range and seemed to have contributed to the hypertriglyceridaemia in these patients. Plasma FFA turnover rate ranged between 102 and 439 μmol/min. and m² body surface area. On the average splanchnic FFA mobilization and uptake were about 30 and 60 per cent respectively of total FFA turnover rate. Significant positive correlations were found for the interrelationships between the three plasma FFA total and splanchnic transport parameters. Significant positive correlations were found between the three plasma TG “turnover rates” and total and splanchnic turnover of plasma FFA in subjects with normal plasma TG concentrations. Some patients with hypertriglyceridaemia fell outside the intervals of 99 per cent confidence of the regression analyses for the normo-triglyceridaemic subjects. This group had higher TG “turnover rates” than “expected” from plasma FFA turnover rates and may represent a distinctive group of hypertriglyceridaemia from the point of view of pathogenesis. It was concluded that all patients with hypertriglyceridaemia who were investigated had decreased “fractional turnover rates” of plasma TG indicating a decreased removal capacity which might be a primary cause of the hypertriglyceridaemia although inflow of plasma TG seemed to be an essential contributing factor in half the number of patients.     

HEMOGLOBIN AND PLASMA PROTEIN : SIMULTANEOUS PRODUCTION DURING CONTINUED BLEEDING AS INFLUENCED BY DIET PROTEIN AND OTHER FACTORS

Given healthy dogs, fed abundant iron and a limited protein diet, with sustained anemia due to simple bleeding, we can study the capacity of each animal to produce new hemoglobin and plasma protein. Some dogs can produce much hemoglobin and enough new plasma protein to maintain the plasma protein concentration at approximately a low normal level. It is probable that their plasma protein producing capacity is not fully extended (Table 2). Other dogs (Table 5) can produce the same amount of hemoglobin but a hypoproteinemia develops and continues which should mean a maximal stimulus to produce new plasma protein. In such dogs we have strong stimuli to produce simultaneously new hemoglobin and new plasma protein. The ratio of plasma protein to hemoglobin varies from 40 to 60 per cent. The total new formed blood protein may amount to 30 to 40 per cent of the total diet protein intake which shows that some dogs have remarkable capacity to conserve and use diet protein. In this emergency of simultaneous depletion of hemoglobin and plasma protein levels, the dog gives preference to hemoglobin manufacture no matter what one of the listed food proteins is tested.