Blood pyruvic acid

A5. Amatuzio, D. S., Schrifter, N., Stutzman, F. L., and Nesbitt, S., Blood pyruvic acid response to intravenous administered glucose or insulin in the normal and in patients with liver disease and with diabetes mellitus. J. Clin. Invest. 31, 751 (1952). 

B16. Bianchessi, M., Estimation of blood pyruvic acid in liver diseases and in pancreatic diabetes. CUn. Chim. Acta 3, 179 (1958). 

D5. Dawson, A. M., de Croote, J., Rosenthal, W. S., and Sherlock, S., Blood pyruvic acid and alpha-ketoglutaric acid levels in liver disease and hepatic coma. Lancet i, 392 (1957). 

The most logical explanation for the increase in blood pyruvic acid is that the increase results from the blocking of pyruvic decarboxylase. However, in experiments in which blood pyruvic acid levels in thiamine-deficient animals were correlated with the changes in the adrenals, it was concluded that the increase in blood pyruvate can be correlated more closely to adrenal hypertrophy than to thiamine deficiency. Furthermore, in thiamine-deficient adrenalec-tomized and hypophysectomized animals, pyruvemia was much less than in the controls. Finally, cortisone administration increases the level of blood pyruvate. Consequently, pyruvemia in thiamine-deficient animals may result from immediate stress caused by the deficiency and from progressive block of pyruvic decarboxylase due to the slow depletion of coenzyme. 

Gross and associates found an increased loss of fat in the stools in patients with cirrhosis and postulated defective formation of bile salts as the cause. Serum concentrations of sodium, potassium, calcium, and phosphorus have been found to be lower than normal, and blood pyruvic acid levels elevated, in patients with decompensated alcoholic cirrhosis. When an adequate diet was instituted, these findings reverted to normal. The low levels of calcium and phosphorus may have resulted from an increase... 

If the salicylate level continues to rise, the respiratory centers become depressed, the PC02 level becomes elevated, and the blood pH becomes more acidic, causing respiratory acidosis. Dehydration, reduced bicarbonate levels, and the accumulation of salicylic acid, salicyluric acid resulting from metabolism of aspirin, and lactic and pyruvic acid resulting from deranged carbohydrate metabolism may cause metabolic acidosis. 

Brain function is dependent upon ready availability of energy by aerobic metabolism. This energy is provided by aerobic glycolysis, the breakdown of glucose blood sugar to pyruvic acid with 02 as an electron acceptor. Therefore, brain cells and other nerve cells are highly susceptible to interruptions in the supply of either 02 or blood glucose. 

Plasma The fluid component of blood that consists of 55% of total blood volume is comprised mostly of water and a small percentage of solutes. Solutes are glucose, protein, lipids, amino acids, electrolytes, minerals, lactic and pyruvic acids, hormones, enzymes, oxygen, and carbon dioxide. 

A 3-month-old boy presents with poor feeding and growth, low muscle tone (hypotonia), elevation of blood lactic acid (lactic acidemia), and mild acidosis (blood pH 7.3 to 7.35). The ratio of pyruvate to lactate in serum is elevated, and there is decreased conversion of pyruvate to acetyl coenzyme A in fibroblasts. Which of the following compounds might be considered for therapy ... 

Compound derived from poppy seed oil. Inhibits oxidation of pyruvic acid, which accumulates in the blood. Used as antimicrobial to control dental disease but also toxic - cause of epidemic dropsy. 

This is the normal body process whereby glucose or blood sugar is converted ultimately to carbon dioxide and water. Following the ten-step conversion of glucose to pyruvic acid, the pyruvic acid is then converted to the end products of carbon dioxide and water via what is variously called the tricarboxylic acid, or citric acid, or Krebs cycle. The conversion is strongly exothermic, fueling the body s internal processes and its external activities. 

The concentration of a-ketoglutaric acid is much higher in urine than in blood (the reverse being generally true for pyruvic acid) (B18). 

I.I. Pyruvic Acid. Pyruvic acid is the predominant a-keto acid of human blood, whereas a-ketoglutaric acid predominates in human urine... 

B18). The mean levels of pyruvic acid in normal human whole blood found by most authors using paper chromatographic techniques are 0,35-0,92 mg% (M2). Specific enzymatic methods (H15, H23, SIO, S38) have given similar results by such a technique, Strohmeyer et al. (S38) found, for instance, 0.77 0,19 mg%. The same reasons as those discussed in the case of a-ketoglutaric acid explain why the most reliable data deal with whole blood and not plasma. 

Many factors aflFecting the pyruvate level in blood and urine, especially muscular exercise, have been studied they have been reviewed previously (A2, L15, M24, P4, S21, T8). Among the newer studies concerning the effect of hormones on blood pyruvate, we shall only mention that the blood level of pyruvic acid is increased after administration of adrenal steroids, which seem to have an inhibitory effect on the utilization of pyruvate (H18). 

We shall focus attention rather on studies concerning the altered blood and urine concentrations of pyruvic acid and of the acids of the tricarboxylic acid cycle, since they are capable of giving information about the still unsolved problem, whether or not there exists a definite disturbance of that cycle during diabetes mellitus. 

Blood pyruvate concentration is not altered in most cases of diabetes mellitus (A5, D14, S28). Previous results, obtained by use of the colorimetric technique of Friedemann and Haugen (F12) and showing an apparent high pyruvate level during diabetic coma, are erroneous and are due to the interference of acetoacetic acid on pyruvic add determination with that technique (Lll, L12, L13). 

The data summarized before, showing the coexistence of usually normal blood pyruvate and a-ketoglutarate levels with a probable decrease of blood citrate and inconstant abnormahties in the response of blood pyruvate and citrate to glucose and pyruvate administration, do not as yet allow a firm statement as to whether or not there exists a definite disturbance in one or more reactions of the tricarboxylic acid cycle during diabetes mellitus. 

In the light of these findings, it is interesting to discuss the mechanism responsible for the elevation of the blood lactic and pyruvic acids as well as of the tricarboxylic acid cycle acids. 

Other Organic Acids. Pyruvic acid, the clearance of which is also reduced during renal failure (Z4), has been found to be slightly increased in the blood of a few patients with chronic renal diseases (B18). 

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