Erythrocytes magnesium

An alkaline pyrophosphatase from rat liver cytoplasm has been partially purified and characterized (24) the corresponding enzyme from mice is inhibited by Mg J+-ADP and free PPj, and free Mg2+ has been implicated as an allosteric activator (23). Partial heat inactivation results in loss of the apparent allosteric effects. Rat liver mitochondrial pyrophosphatase, which is inhibited by adenine nucleotides (36), appears to be bound to the inside of the inner mitochondrial membrane (37). This enzyme, after solubilization, has been separated into two fractions which have somewhat different specificity (24, 38). A pyrophosphatase strongly simulated by sulfhydryl reagents (39) has been partially purified from brain tissue (40). The mono-magnesium PPj complex appears to be the true substrate for this enzyme (41). Pynes and Younathan have purified a pyrophosphatase 1800-fold from human erythrocytes (43). The properties of this enzyme are strikingly similar to those of the yeast enzyme the major difference appears to be the more rigid substrate specificity of the erythrocyte enzyme in the presence of Znz. ... 

Olehy DA, Schmitt RA, Bethard WF. 1966. Neutron activation analysis of magnesium, calcium, strontium, barium, manganese, cobalt, copper, zinc, sodium, and potassium in human erythrocytes and plasma. J Nucl Med 6 917-927. 

Laughlin, M. R., and Thompson, D. (19%). The regulatory role for magnesium in glycolytic flux of the human erythrocyte. /. Biol. Chem. 271,28977-28983. 

Caffeine is also a potent stimulant of gastric juice, hydrochloric acid, and pepsin secretion. The serum gastrin concentration may be increased by as much as five times after the ingestion of three cups of coffee. Coffee has a diuretic effect and also increases the excretion of erythrocytes and renal tubular cells in the urine. Caffeine increases the absolute amounts of sodium, potassium, calcium, and magnesium in urine—an effect not observed with decaffeinated coffee. 

Serum or plasma must be separated from the clot or red blood ceEs as soon as possible to prevent an increase in serum magnesium because of cell leakage. Because erythrocytes contam higher concentrations of magnesium than... 

For adults, the reference interval for serum magnesium is 1.7 to 2.4 mg/dL (0.66 to 1.07 mmol/L). Magnesium concentrations in erythrocytes are approximately three times those of serum. Conversion factors for the units used to express magnesium concentration are given below ... 

The free energy of hydrolysis of ATP is also affected by Mg " " and the physiological substrate is Mg " " ATP (or Mg ATP ). The presence of magnesium ions favors ATP hydrolysis because both ADP and Pi have higher affinity (about six times) for Mg + than ATP. In vivo, the AG value for ATP hydrolysis is probably much higher than AG° owing to the prevailing intracellular concentration of the reactants and products (in erythrocytes, —12.4 kcal/mol). 

Hemberg S, Howe G, Virkola P, et al. 1969. Magnesium and zinc values of erythrocytes and plasma for workers exposed to carbon disulphide. Work Environ Health 6 9-13. 

Genetically determined variations in the distribution of lithium between plasma and erythrocytes have been found in sheep (Schless et. al. 1975). Likewise, depressive patients react differently to lithium treatment, with heredity a probable contributory factor, as has been shown investigations conducted in twins. A hereditary recessive primary hypomagnesemia that is accompanied by a low level of calcium in the blood leads to tetany. This is presumably caused by a nonfunctional magnesium resorption in the intestine (Lombeck and Bremer... 

Davidsson, L., Ziegler, E., Zeder, C., Waiczyk, T. Murrell, R. (2005) Sodium iron EDTA [NaFe (lll)EDTA] as a food fortificant erythrocyte incorporation of iron and apparent absorption of zinc, copper, calcium, and magnesium from a complementary food based on wheat and soy in healthy infants. Am. J. Clin. Nutr. 81,104-109. 

A significant effort was necessary to obtain accurate results for selenium in blood, plasma, and erythrocytes [27]. Iron causes a spectral interference at the selenium line at 196 nm if a continuum source background corrector is used, causing erroneous results particularly in blood and erythrocytes. Zeeman effect background correction is therefore mandatory for the determination of selenium in clinical samples. In addition, some of the previously recommended chemical modifiers were found to stabilize the different selenium species differently, so that some of them may be lost in the pyrolysis stage. A mixture of palladium and magnesium nitrates was found to solve the problem and prevent any preatomization losses [28]. 

Bohn, T., Walczyk, T., Davidsson, L., Pritzkow, W., Klingbeil, P., Vogl, J., and Hurrell, R.F. (2004) Comparison of urinary monitoring, faecal monitoring and erythrocyte analysis of stable isotope labels to determine magnesium absorption in human subjects. Br. J. Nutr., 91 (1), 113-120. 

The enzyme 5-phosphoribosyl-l-pyrophosphate (PRPP) synthetase (EC 2.7.6.l) catalyzes the synthesis of PRPP from ribose-5-phosphate (R-5-P) and adenosine 5 triphosphate (ATP) in the presence of magnesium and inorganic phosphate (9-ll). In the present communication we report studies on a mutant superactive PRPP synthetase in the erythrocytes of two brothers with excessive purine production associated with gout and uric acid lithiasis. In these two patients the serum uric acid reached 13.5 and 13.6 mg percent and the urinary 24 hours uric acid excretion 2400 mg and 2250 mg, respectively. All other members of the family examined were clinically and biochemically normal, except for the mother of the patients who had hyperuricosuria, 1100 mg per 24 hours. 

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