Comparative Erythrocyte Metabolism in Marsupials and Monotremes

Concentrations of ATP and DPG, activities of 10 enzymes and the glycolytic rates were measured in the erythrocytes of 11 species of marsupials and two species of monotremes. Mean DPG concentrations were greater in the erythrocytes of marsupials than those of eutherian mammals. The opposite is true of ATP. Significant findings from the results of enzyme activities were: high activity of hexokinase (7.39 + 0.82 EU/g Hb) in the short-beaked echidna, pyruvate kinase (37.49 + 1.0 EU/g) Hb in bridled nailtail wallaby and glucose-6-phosphate dehydrogenase (G6PD; 41.66 + 1.24 EU/g Rb) in black-striped wallaby. About 6- to 7-fold difference in the activity of G6PD levels between the two species of wombats was confirmed. Glucose phosphate isomerase activity was also shown to be twice as high in the red cells of the common wombat compared with those of the southern hairy nosed wombat. There were wide variations in the glycolytic rate among the species examined

Comparative Study Of The Antioxidant Defence Systems In The Erythrocytes Of Australian Marsupials And Monotremes

A comparison of the erythrocyte (RBC) antioxidant metabolites and enzymes in nine marsupial and two monotreme species was carried out. Reduced glutathione (GSH) concentrations were comparable with those reported for other marsupial and eutherian species. An important finding was that the erythrocytes of the southern hairy nosed wombat regenerated GSH faster than the erythrocytes from its close relative, the common wombat. The activities of glutathione-S-transferase, NADH methaemoglobin reductase, superoxide dismutase, and glutathione peroxidase (GSH-Px), showed similar levels and extents of variation as those observed in other marsupial and eutherian species. Catalase activities in the marsupials were lower than those measured in the two monotreme species and much lower than those reported in eutherian species. A negative correlation, significant at P < 0.05, was observed between GSH-PX and catalase activities in the RBC of the marsupials. Since both these enzymes "detoxify" H202, there appears to be a reciprocal relationship between the activities of these enzymes in marsupial RB

Hematology and erythrocyte biochemistry of spectacled hare-wallaby, Lagorchestes conspicillatus (Macropodidae Marsupialia)

Hematology and the red cell enzymes, metabolites, and rates of lactate production were measured in a small marsupial, the spectacled hare-wallaby Lagorchestes conspicillatus. In common with other marsupials of similar body weights, the red cells of this wallaby were found to have low levels of ATP and higher levels of 2,3-diphosphoglycerate (DPG) and produced no lactate when incubated with inosine. One of the five animals examined was suffering from anemia (hematocrit of 22.0% and hemoglobin concentration of 7.2 g/dl compared with the normal values of 46.6% and 15.8 g/dl, respectively); its red cells had almost twice the concentrations of ATP and DPG and had significantly higher activities of several enzymes of the glycolytic pathway

Levels of glycolytic enzymes and metabolites in the red blood cells of the red-legged pademelon, Thylogale stigmatica (macropodidae: marsupialia)

1. 1. Haematology, red cell enzymes and metabolites and the rates of lacate production by the red blood cells incubated with different substrates were measured in the blood from a small marsupial, the red-legged pademelon (Thylogale stigmatica). 2. 2. In comparison with other marsupials of similar body weight, pademelon red cells have lower levels of adenosine triphosphate (ATP) and a lower activity of glutathione S-transferase. 3. 3. Red cells incubated with inosine did not produce lactate, a finding which is not uncommon in marsupials

Glucose-6-phosphate dehydrogenase and oxidant sensitivity of erythrocytes of three species of wombats

The investigations presented in this paper were undertaken to examine the antioxidant defence systems in the erythrocytes of three extant species of wombats: the common wombat (CW) (Vombatus ursinus), the southern hairy-nosed wombat (SHW) (Lasiorhinus latifrons) and the northern hairy-nosed wombat (NHW) (Lasiorhinus krefftii). Some of the important observations were: (1) the activity of glucose-6-phosphate dehydrogenase was 5.14 ± 0.96 enzyme units/g haemoglobin (EU/gHb) in CW, 35.69 ± 1.02 EU in SHW and 30.71 ± 1.49 EU in NHW and the levels of glucose phosphate isomerase were 40.1 ± 3.39, 93.2 ± 1.96 and 74.9 ± 4.9 EU/gHb, respectively and (2) the erythrocytes of CW were found to be more sensitive to oxidant stress as measured by the degree of lipid peroxidation, haemolysis, number of Heinz bodies, and the methaemoglobin formation in the intact cells and/or haemolysates treated with three different oxidising agents - acetylphenylhydrazine, sodium nitrite and hydrogen peroxide. The CW lives in a temperate environment and the SHW, and NHW live in arid to semi-arid environments. The consequences in terms of antioxidant defence requirements are discussed

Erythrocyte metabolism in the Koala, the common brushtail possum and the whiptail wallaby

Erythrocyte metabolism was studied in the koala (Phascolarctos cinereus), the common brushtail possum (Trichosurus vulpecula) and the whiptail wallaby (Macropus parryi). Aspects of metabolism studied were the levels of ATP, 2,3-diphosphoglycerate (2,3-DPG) and reduced glutathione (GSH), activities of erythrocyte enzymes, glycolytic rate, the rate of glutathione S-conjugate transport (GCT), susceptibility of erythrocytes to an oxidising agent and the effect of eucalyptus oil on the red cells. Some of the major findings were that compared to common brushtail possum and the whiptail wallaby, the koala red cells (a) produced significantly greater amounts of lactate; (b) had significantly lower activity of glutathione S-transferase, (c) had significantly lower rate of GCT, (d) were more susceptible to oxidant stress induced by acetylphenylhydrazine (APH) and (e) exhibited a greater degree of haemolysis when incubated with eucalyptus oil