Kinetics of Vascular and Extravascular Protein Exchange in Unbled and Bled Dogs

Wasserman, Karlman; Joseph, Jeanne D.; Mayerson, H. S.

doi:10.1152/ajplegacy.1955.184.1.175

Cited by 48 publications

(13 citation statements)

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“…Slight increases in plasma volume play some part in this but more importantly a greater proportion of total body albumin mass is lost from the extravascular space rather than from the plasma. These observations substantiate those of many other workers using different techniques and a wide variety of experimental subjects ( In protein malnutrition the alterations described are a consequence of lowered albumin synthetic rates but similar reductions in extravascular albumin mass also occur after plasmapheresis (Yuile, Lucas, Neubecker, Cochrane & Whipple, 1959; Matthews, I 961) and haemorrhage (Wasserman, Joseph & Mayerson, 1956) when presumably synthetic rates are normal or elevated, and consequently James & Hay (1968) suggested that a fall in extravascular albumin mass is related to the depletion of the intravascular mass and not to the process by which this occurs; any explanation offered for the redistribution of whole body albumin mass in protein deficiency should take this point into account.…”

Section: Total Body Albumin Mass and Distributionsupporting

confidence: 87%

Whole-body albumin mass and distribution in rats fed on low-protein diets

Coward

Sawyer

1977

Br J Nutr

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I . From 5 weeks of age, control and experimental rats were given diets containing 2x0 and 31 gprotein/kg respectively, and killed for analysis at 0, 2, 5, 8, 12 and 20 d after the start of the experiment. At these times estimates were made of plasma albumin concentration, plasma volume and total vascular and extravascular albumin mass.2. Plasma albumin concentrations were significantly lower in the experimental animals when compared to controls at 8, I Z and 20 d but plasma volumes (ml/kg body-weight) tended to be greater in the former animals. Total vascular albumin mass (g/kg body-weight) was significantly less in experimental animals compared to controls at 8 and 5. It was concluded that measurement of plasma albumin concentration does not indicate the true extent of whole-body albumin losses in protein deficiency since total vascular albumin mass is, to some extent, maintained at the expense of extravascular albumin mass.

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Section: Total Body Albumin Mass and Distributionsupporting

confidence: 87%

Whole-body albumin mass and distribution in rats fed on low-protein diets

Coward

Sawyer

1977

Br J Nutr

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“…The immediate fall in the extravascular activity in phase 2 is associated with a fall in the albumin synthetic rate. Plasmapheresis or bleeding of animals on normal protein intakes, with presumably normal or increased synthetic rates, also produces a fall in extravascular mass (47,48). This suggests that the shift in albumin into the intravascular compartment is related to the depletion of intravascular albumin mass per se, and not to the process by which this occurs.…”

Section: Discussionmentioning

confidence: 99%

Albumin metabolism: effect of the nutritional state and the dietary protein intake

James¹,

Hay²

1968

J. Clin. Invest.

176

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A B S T R A C T Nine malnourished and nine children who had recovered from malnutrition were given a single injection of albumin-131I and were studied during consecutive periods in which the dietary protein was changed.Malnourished children had significantly lower catabolic rates of albumin than had recovered children on the same protein intake. Both nutritional groups, however, showed a progressive fall in catabolic rate after 3-5 days on a low protein diet (0.7-1.0 g/kg per day), and the maximum effect was seen in the 2nd wk of low protein feeding. The catabolic rate could return to normal within 3 wk in a malnourished child fed 4 g of protein/kg per day.The albumin synthetic rate was measured by a computer technique suitable for nonsteady-state conditions. The synthetic rate in the malnourished groups (101 mg/kg per day) fed on a low protein diet was significantly lower than the rate in the recovered groups (148 mg/kg per day). The synthetic rate responded rapidly to a change in diet; when the rate fell, the intravascular albumin mass was maintained by two compensating mechanisms: (1) a net transfer of extravascular albumin into the intravascular pool; and (2) by a delayed fall in the catabolic rate. The net transfer of albumin into the intravascular compartment diminished as the catabolic rate fell.Adaptation to a low protein diet was associated with: (a) low synthetic and catabolic rates of albumin; (b) a reduced extravascular albumin mass;

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“…This would be in agreement with the results of some other workers. Wasserman, Joseph and Mayerson (17) conclude from plasmapheresis and infusion experiments in dogs that albumin is first replaced from the extravascular pool and later by increased synthesis. Rodionov and associates (16) reach the same conclusions from plasmapheresis experiments in dogs with and without liver denervation, but they also find a large increase in globulins after bleeding.…”

Section: Discussionmentioning

confidence: 99%

Effects of Plasmapheresis on Albumin Pools in Rabbits

Matthews¹

1961

J. Clin. Invest.

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The normal regulation of intravascular plasma protein mass has not been fully investigated. It has long been known that plasma proteins rapidly return to normal concentrations after plasmapheresis, but the means by which this takes place has not been clearly demonstrated. In pathological states, such as nephrosis and hypercatabolic hypoproteinemia, where there may be a steady loss of plasma protein, some compensatory mechanism (see next paragraph) must be involved in cases in which the intravascular plasma proteins are in a steady state. Frequently the protein concentration alone is determined, so that it is not known whether changes are due to variations in plasma volume or in total intravascular protein mass. A steady state can only be said to exist when the plasma protein synthesized is equal to that catabolized, so that the total mass of protein, but not necessarily the concentration, is constant.Disturbances of intravascular protein mass could be compensated for by a) change in synthesis rate, b) change in catabolic rate, c) net transfer of protein between extravascular and intravascular protein pools or d) a combination of several of these. There is also the possibility that the proportion of the different protein fractions is altered and that loss of one fraction is replaced by an increase of another fraction.The purpose of this investigation was to obtain further evidence on this problem by removing protein by plasmapheresis and observing the effect on the catabolic rate, intravascular pool mass, concentration and volume, and on the sum of synthesis rate plus net transfer rate from extravascular to intravascular pool. Rabbits on a normal diet were used, and a single protein fraction, albumin, was considered.I131-rabbit albumin was injected intravenously into rabbits, and plasma albumin specific activity (microcuries per gram), total body radioactivity * Present address: Radiotherapeutic Research Unit, Hammersmith Hospital, London, England. and urinary radioactivity were measured. It is assumed throughout that I131-albumin behaves as normal rabbit albumin (1, 2), that after catabolism the I131 is rapidly excreted, and that there is rapid mixing in each separate protein pool so that within any one pool the specific activity is uniform.A control period of ten days from the injection was allowed before starting plasmapheresis. The normal catabolic rate and pool masses were thus determined for each animal. Daily determinations of intravascular protein mass, concentration and volume were also made throughout each experiment in a control animal not subject to plasmapheresis.Intravascular protein mass and plasma volume were determined by isotope dilution. Since the proportion of albumin to total plasma protein was found to be constant throughout the experiment, albumin masses could be calculated from total protein masses. METHODS TheoreticalExtravascular pool. During the control period, the extravascular protein mass was determined by the equilibrium time method (3-5). In this method the ratio of extravascular t...

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Kinetics of Vascular and Extravascular Protein Exchange in Unbled and Bled Dogs

Cited by 48 publications

References 0 publications

Whole-body albumin mass and distribution in rats fed on low-protein diets

Whole-body albumin mass and distribution in rats fed on low-protein diets

Albumin metabolism: effect of the nutritional state and the dietary protein intake

Effects of Plasmapheresis on Albumin Pools in Rabbits

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