Iron and Protein Kinetics Studied by Means of Doubly Labeled Human Crystalline Transferrin*

Katz, Jay H.

doi:10.1172/jci104440

Cited by 109 publications

(34 citation statements)

References 34 publications

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“…Fractional catabolic rates derived from iodinated transferrin studies generally have been somewhat higher. The study of Cromwell (36) showed an average catabolic rate of 0.62% of the plasma pool/hr, that of Awai and Brown 0.67%o/hr (37), Jarnum and Lassen 0.77%/hr (38), and Katz 0.95%/hr (39).…”

Section: Interpretation Of Resultsmentioning

confidence: 99%

Direct measurement of the rates of synthesis of plasma proteins in control subjects and patients with gastrointestinal protein loss

Wochner¹,

Weissman²,

Waldmann³

et al. 1968

J. Clin. Invest.

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A B S T R A C T The guanido carbon of hepatic arginine is the common precursor of urea and of the arginine of plasma proteins synthesized in the liver. It is possible to measure the momentary synthetic rates of plasma proteins by "pulse labeling" this arginine pool with bicarbonate-14C. In the current study, this method has been adapted in order to use urinary urea data and was applied to control subjects and patients with gastrointestinal protein loss. The assumptions required for this determination are discussed.There was close agreement between albumin synthetic rates measured by this method and albumin catabolic rates derived from simultaneous albumin-131I studies, supporting the validity of the method and suggesting that there is relatively little fluctuation in the rate of albumin synthesis from time to time. The albumin synthetic rates in six control subjects averaged 5.8 mg/kg per hr, while those of five patients with gastrointestinal protein loss averaged 7.2 mg/kg per hr. Thus in these patients, there was relatively little acceleration of albumin synthesis in response to continued loss of plasma proteins into the gastrointestinal tract.Fibrinogen synthetic rates averaged 1.9 mg/kg per hr in five control subjects and 3.2 mg/kg per hr in five patients with gastrointestinal protein

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Section: Interpretation Of Resultsmentioning

confidence: 99%

Direct measurement of the rates of synthesis of plasma proteins in control subjects and patients with gastrointestinal protein loss

Wochner¹,

Weissman²,

Waldmann³

et al. 1968

J. Clin. Invest.

View full text Add to dashboard Cite

show abstract

“…The methods employed in the preparation and analysis of iodinated transferrin are reported in full detail elsewhere (19). The following criteria were used to -determine the structural and functional integrity of the I"'l-labeled transferrin:…”

Section: Methodsmentioning

confidence: 99%

“…The stability of the iodine complex with transferrin was further attested to by the fact that incubating P1`-transferrin with a large excess of human albumin did not result in the attachment of any of the I" to the albumin, as determined by subsequent electrophoretic separation of the proteins followed by autoradiography. 7) On injection into human subjects iron bound to this iodinated transferrin was cleared from the plasma at a normal rate and was utilized by red cells to a normal extent (19 (31,32).…”

Section: Methodsmentioning

confidence: 99%

“…It should be noted, however, that in vivo only a very small fraction of the total body pool of transferrin would be attached to the membranes of immature red cells at any one time. Based on current estimates of the volume of erythroid marrow and on the present studies, the total quantity of cell-fixed transferrin at any given moment would be of the order of 10 or 20 mg. As compared to the total exchangeable pool of transferrin, estimated to be at least 14 g in the average adult male (19), fluctuations in the cellular phase of transferrin would have no discernible effect either on the plasma level or on the rate of degradation of transferrin.…”

Section: Uptake Of I'31-transferrin By Reticulocytesmentioning

confidence: 96%

“…This raised the possibility that transferrin itself became attached to the cell surface or actually entered the red cell transiently while unloading its iron. Since it is known from comparison of the rates of turnover of iron (6)(7)(8) and of transferrin (17)(18)(19) that 314 transferrin is not consumed during iron-unloading, it must be assumed that if transferrin attaches to the cell, or enters it, this is a reversible process. Recent studies (20) revealed that immature red cells of man do manifest a protein on their surfaces, and this protein has the immunologic properties of transferrin.…”

mentioning

confidence: 99%

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