Albumin synthesis

Approximately 80% of patients with a GFR less than 20 to 30 mL/minute develop metabolic acidosis.38 Metabolic acidosis can increase protein catabolism and decrease albumin synthesis, which promote muscle wasting, and alter bone metabolism. Other consequences associated with metabolic acidosis in CKD include worsening cardiac disease, impaired glucose tolerance, altered growth hormone and thyroid function, and inflammation.38... 

Albumin has a molecular mass of approximately 66 000 and is synthesized at a rate of about 12 g, equal to 3% of total body albumin, per day to replace that which is degraded or lost. Impaired albumin synthesis and therefore a low plasma albumin concentration, is a hallmark of chronic liver disease. Several functions can be ascribed to albumin including osmotic (oncotic) pressure regulation of the plasma and a non-specific transport protein for ligands such as calcium, fatty acids, drugs and bilirubin. 

Sodium retention and hypo albumin aemi a are constant features. The former appears consequent on disturbed blood volume distribution, withslanch-nic dilatation and reduced effective central arterial blood volume leads to sodium retention. Hypoalbu-minaemia associated with reduced hepatic albumin synthesis, and raised portal pressure associated with obstruction to flow, as well as active sodium retention all predispose to ascites. Hypoalbuminaemia is associated with reduced hepatic synthesis. 

Kaysen GA, Gambertoglio J, Felts J, Hutchison FN. Albumin synthesis, albuminuria and hyperlipemia in nephrotic patients. Kid Int 1987 31 1368-1376. 

Albumin is synthesised in the liver and has a long half-life of around 20 days. Mrs MW s low serum albumin is indicative of chronic liver disease. Albumin synthesis is also depressed in states of poor nutrition. 

An elevation of ChE activity can be detected in fatty liver, obesity, diabetes mellitus, exudative enteropathy, nephrotic syndrome, hyperthyroidism, Meulengracht s icterus, chronic obstructive jaundice, etc. Specificity in liver diseases is 61%, and sensitivity is 49%. In cirrhosis, however, sensitivity is 88% normal ChE therefore widely excludes cirrhosis. In connection with other hepatobiliary enzymes, ChE can be useful in the diagnosis and assessment of the course of liver disease. There is a very good correlation of ChE activity with coagulation factors in liver diseases however, the correlation is less significant with albumin synthesis. 

Single postprandial doses of 28 g or 71 g of alcohol resulted in blocked albumin synthesis or albumin and fibrinogen synthesis respectively. (142)... 

In cirrhotic patients, a reduced synthesis rate of most proteins is found at an early stage, with albumin synthesis being the least compromised factor at first. Fat storage, muscle mass and protein turnover are reduced. This ultimately leads to catabolism (so-called stress metabolism) and increasing muscular atrophy (so-called wasting syndrome). The latter condition can also result from sympathicotonia with elevated catecholamine values similarly, decreased values of IGFl inhibit the formation of muscle tissue. 

Ballmer, RE. Walshe, D., McNurlan, M.A., Watson, H., Brunt, P.W., Garllck, P.J. Albumin synthesis rate in cirrhosis correlation with Child-Turcotte classification. Hepatology 1993 18 292 -297... 

Since albumin is synthesized in the liver (M23), the reduction in albumin found in most forms of liver disease has been attributed to decreased synthesis. The isolated microsome fraction of liver is capable of incorporating amino acids into albumin, but the ribonucleoprotein particles do not seem to be the site of protein synthesis (D6). A reduction in albumin synthesis may be one result of a shortage of ATP (adenosine triphosphate) (K34). 

Rothschild et al.109 found that the addition of tryptophan to isolated perfused livers of rabbits treated with CC14 aided in the recovery of albumin synthesis. This study is consistent with the findings that tryptophan had a beneficial effect on hepatic polyribosomes and protein synthesis in rats treated with CC14. Thus, tryptophan may be a useful therapeutic agent for the livers of experimental animals injured with CC14. 

Rothschild, M. A., Oratz, M., Mongelli, J., and Schreiber, S. S., Alcohol-induced depression of albumin synthesis Reversal by tryptophan, /. Clin. Invest., 50, 1812, 1971. 

Steinfeld, J. L., Difference in daily albumin synthesis between normal men and women as measured with I-labelled albumin. J. Lab. Clin. Med. 65, 904-911 (1960). 

In acute hepatocellular damage, albumin synthesis is reduced or ceases, leading to hypoalbuminaemia and the development of oedema and/or ascites. The failure of synthesis of clotting factors also leads to an increased tendency to haemorrhage or. in severe cases, to intravascular coagulation. 

In cases of severe protein malnutrition (kwashiorkor), the concentration of the plasma proteins decreases, as a result of which the osmotic pressure of the blood decreases. As a result, fluid is not drawn back to the blood and instead accumulates in the interstitial space (edema). The distended bellies of famine victims are the result of fluid accumulation in the extravascular tissues because of the severely decreased concentration of plasma proteins, particularly albumin. Albumin synthesis decreases fairly early under conditions of protein malnutrition. 

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