Synthesis of factor II antigen by isolated perfused rat liver

Owens, Michael R.; Miller, Leon L.; Cimino, Catherine D.

doi:10.1016/0304-4165(81)90172-0

Cited by 15 publications

(13 citation statements)

References 24 publications

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“…Most plasma proteins are synthesized by liver parenchymal cells (19,20), which utilize both plasma-and cellular-derived amino acids as precursors for such exported proteins. We employed a sophisticated stable isotope infusion method to quantitate the synthesis rate of plasma fibronectin in healthy subjects and injured patients and to compare its synthesis to a well-documented acute phase protein, such as fibrinogen.…”

Section: Discussionmentioning

confidence: 99%

“…1 (19,20), the second was the APE of urinary hippurate which may be considered to be equivalent to the intracellular enrichment (21,22). For completeness, we utilized both approaches, i.e., with Si(t) equal to the plasma glycine APE, and with Si(t) equal to the urinary hippurate APE to calculate the endogenous rate ofsynthesis ofplasma fibronectin and fibrinogen.…”

Section: Determination Ofthe Synthesis Rate Offibronectinmentioning

confidence: 99%

See 1 more Smart Citation

Plasma fibronectin synthesis in normal and injured humans as determined by stable isotope incorporation.

Thompson¹,

Blumenstock²,

Saba³

et al. 1989

J. Clin. Invest.

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In humans, plasma fibronectin decreases early after operative injury, burn, or trauma, followed by a rapid restoration with a secondary decline typically observed if such patients become septic. We determined the rate of plasma fibronectin and plasma fibrinogen synthesis in normal subjects and injured patients using a stable isotope incorporation technique with ['5NMglycine. During a constant 14-h infusion of M15NJglycine, the enrichment of I'5Njglycine in both the free plasma glycine precursor pool as well as the urinary hippurate pool was determined; the latter used as an estimate of intracellular hepatic precursor enrichment. [15NjGlycine enrichment in both plasma fibronectin and fibrinogen was also quantified. The synthesis rate (Js/V) expressed in micrograms per milliliter of plasma per hour and the fractional synthesis rate (FSR) expressed as percentage of the plasma pool produced per day were determined. In normal subjects, the FSR for plasma fibronectin using "5N enrichment into urinary hippurate was 35.35 ±1.46%/d, whereas the Js/V was 4.45±0.19 gg/ml plasma per h. In normal subjects, the FSR for plasma fibronectin using 15N enrichment into free plasma glycine was 14.73±0.63%/d, whereas the Js/V was 1.98±0.09 ,ug/ml plasma per h. Early (2-3 d) after burn injury, fibronectin synthesis was increased (Js/V = 5.74±0.36; P < 0.05), whereas later after injury, fibronectin synthesis began to decline (Js/V = 3.52±0.24; P < 0.05) based on 15N enrichment of urinary hippurate. In contrast, the Js/V and FSR of plasma fibrinogen, a well-documented acute-phase plasma protein, revealed a sustained elevation (P < 0.05) after injury in both the trauma and burn patients. Thus, plasma fibronectin synthesis is elevated early postinjury, which may contribute to the rapid restoration of its blood level. However, once fibronectin levels have normalized, the synthesis of plasma fibronectin appears to decline.

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Section: Discussionmentioning

confidence: 99%

Section: Determination Ofthe Synthesis Rate Offibronectinmentioning

confidence: 99%

Plasma fibronectin synthesis in normal and injured humans as determined by stable isotope incorporation.

Thompson¹,

Blumenstock²,

Saba³

et al. 1989

J. Clin. Invest.

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“…Hepatocytes in culture secrete fibronectin which co-migrates with plasma fibronectin in electrophoretic systems in which fibronectin secreted by cultured fibroblasts does not comigrate (7). Isolated, perfused rat livers produce enough fibronectin to account for fibronectin in plasma (8). Finally, patients with fulminant hepatic failure have low concentrations of plasma fibronectin (9).…”

Section: Fibronectin and Liver Diseasementioning

confidence: 98%

Fibronectin and liver disease

Mosher

1986

Hepatology

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Fibronectin is a glycoprotein found in the extracellular space of most tissues (1-4). It occurs in soluble and insoluble forms. The concentration of fibronectin in circulating plasma is quite high, approximately 30 mg per dl. Fibronectin is also found in amniotic fluid, seminal fluid, joint fluid, cerebrospinal fluid and conditioned medium of many cell types in culture, including hepatocytes (5). Insoluble fibronectin is a component of fibrillar extracellular structures and basal lamina of all tissues with the possible exception of the nervous system.Fibronectin interacts with cells and a number of macromolecules, including fibrin, gelatin and collagen (1-4). Cells specifically adhere to fibronectin and thus use fibronectin to position themselves and move about. Cells also assemble fibronectin into thin extracellular fibrils. Fibronectin in these fibrils is covalently linked together by disulfide bonds and, therefore, is highly insoluble. The fibrils probably serve as a scaffolding to support cell adhesion and movement and also as a nidus for deposition of other connective tissue elements. During blood coagulation, plasma fibronectin is covalently incorporated into the fibrin clot by coagulation Factor XI11 (plasma transglutaminase). Plasma fibronectin has been shown to be an important determinant of the rate of clearance of particulate debris from the circulation and thus is considered to be the major "nonspecific opsonin" of plasma.Soluble fibronectin is composed of two subunits that are approximately 2,250 amino acid residues long and contain 5% carbohydrate. Analyses of amino acid and/ or cDNA sequences indicate that fibronectin is the paradigm of a modular protein (1); more than 90% of the sequence is composed of three different types of homologous units called I, I1 or I11 (Figure 1). There is only one gene for fibronectin, composed of more than 45 exons (coding sequences) and introns (sequences which are removed by splicing during maturation of the mRNA The sequence arginine-glycine-aspartate (RGD) in the tenth block of Type 111 homology seems to be very important for cell adhesion (4). Small peptides with the RGD sequence inhibit cell adhesion, probably by binding to and blocking a specific receptor on the surface of adhering cells. Several kinds of evidence indicate that the adhesion receptor for fibronectin on adhering cells is composed of two integral membrane glycoproteins of molecular weight 140,000. Recent studies indicate that the adhesion receptor for fibronectin is a member of a family of adhesion receptors. Thus, the adhesion receptor for vitronectin, (the other major adhesive protein of blood plasma, but that is another story . . .) is composed of integral membran glycoproteins which also have molecular weights of roughly 140,000, but are different from the glycoproteins of the fibronectin receptor (6).Although many cell types have the capacity to synthesize and secrete fibronectin, most, if not all, circulating fibronectin is produced by hepatocytes. Hepatocytes in culture secrete fibronectin ...

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“…It has been shown that the major source of plasma FN is the fibroblastic cells, the vascular endothelium, the hepatocytes and glomerular cells [7,12,13]. An important factor in the clearance of this protein is its uptake by the reticu loendothelial system [I, 16].…”

Section: Discussionmentioning

confidence: 99%

Plasma Fibronectin Levels in Patients with Chronic Uremia

Schena¹,

Pertosa²,

Germinario³

1986

Nephron

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Plasma fibronectin (FN) concentration was measured in patients with idiopathic glomerulonephritis (GN) with or without impaired renal function, in uremic patients undergoing periodic hemodialysis and in renal transplant patients before and after an acute rejection crisis. Results show normal FN levels in idiopathic GN and in renal transplant patients with normal renal function, while significantly lower levels were found in GN with severe renal damage, in uremia before and after dialysis, and in renal transplant patients during acute and chronic graft rejection. Significant correlations between high serum creatinine values and low plasma FN levels were found in renal transplant patients. These findings suggest that the kidney may influence FN levels in the blood since acute (rejection crisis) and chronic renal failure (uremia) cause low concentrations of this protein, while levels tend to return to normal values in patients with uremia after renal transplantation. We hypothesize that the normal kidney removes or perhaps degrades some substances or hormones that may control the release or synthesis of FN. These substances are not dialyzed by cellophane membranes since low plasma FN levels persist after periodic hemodialysis. Only the renal graft provokes an increase of FN in the blood stream.

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Synthesis of factor II antigen by isolated perfused rat liver

Cited by 15 publications

References 24 publications

Plasma fibronectin synthesis in normal and injured humans as determined by stable isotope incorporation.

Plasma fibronectin synthesis in normal and injured humans as determined by stable isotope incorporation.

Fibronectin and liver disease

Plasma Fibronectin Levels in Patients with Chronic Uremia

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