To examine substrate specificity and susceptibility to lead, erythrocyte 5'-nucleotidase was measured in dogs, cats, cattle and humans, and its relationship to the reticulocyte count in these species was determined. The reticulocyte count in dogs was similar to that in humans, but the count in cats was higher than that in humans. Reticulocytes were not observed in cattle. The activities of cani...

By HELEN QUINCY WOODARD, PH.D. V ARIOUS investigatorst5 have reported that erythrocytes exhibit phosphatase activity at pH values between 4 and 6, and some believe that this is due to two acid phosphatases with maximum activities at about pH 4.2. and .6. Reports on alkaline phosphatase activity have been less numerous.’ ‘ 6 , 7 In the course of an investigation of the glycerophosphatase activit...

From the ability of a concentrated suspension of human erythrocytes to regulate the pH of unbuffered, anisotonic, external media it is possible to calculate the fractional cell volume in which chloride is dissolved. The difference between this volume and the total cell water gives the nonsolvent water (for chloride) of the cell. Nonsolvent water is less than 3% of the isotonic cell volume. The ...

Annexin 7 deficiency has previously been shown to foster suicidal death of erythrocytes or eryptosis, which is triggered by increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) and characterized by cell shrinkage and cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface. Eryptosis following increase of [Ca(2+)](i) by Ca(2+) ionophore ionomycin, osmotic...

Human and rodent erythrocytes are known to be highly permeable to glycerol. Aquaglyceroporin aquaporin (AQP)3 is the major glycerol channel in human and rat erythrocytes. However, AQP3 expression has not been observed in mouse erythrocytes. Here we report the presence of an aquaglyceroporin, AQP9, in mouse erythrocytes. AQP9 levels rise as reticulocytes mature into erythrocytes and as neonatal ...

In order to study 45Ca distribution within erythrocytes, a method was devised that had minimal deleterious effects on the treated erythrocytes. It was observed that newly introduced 45Ca was predominantly recoverable from the cytosol and exchanged relatively slowly with membrane-associated Ca. Younger erythrocytes appeared to have relatively more 45Ca in membrane-associated sites. Erythrocytes ...

From the ability of a concentrated suspension of human erythrocytes to regulate the pH of unbuffered, anisotonic, external media it is possible to calculate the fractional cell volume in which chloride is dissolved. The difference between this volume and the total cell water gives the nonsolvent water (for chloride) of the cell. Nonsolvent water is less than 3 % of the isotonic cell volume. The...