Indirect alkylation of CBA mouse liver DNA and RNA by hydrazine in vivo. A possible mechanism of action as a carcinogen.

Treatment of inbred CBA mice with hydrazine sulfate, a liver carcinogen, plus [14C]formate or L-[methyl-14C]-methionine as a source of "C1" units, produced [14C]7-methylguanine (7-MG) in liver DNA and RNA. This methylated guanine was identified by its chromatographic characteristics in three different systems: on Sephadex G10, on Dowex 50, and by paper co-chromatography with authentic 7-MG. Mice that received [14C]formate alone showed no 7-MG in their DNA or RNA. In addition, mice treated with L-[methyl-14C]methionine alone showed no 7-MG in their DNA. These results suggest that "indirect" alkylation of nucleic acids is a mechanism of cancer initiation by hydrazine.

32P distribution into 2,3-bisphosphoglyceric acid from human erythrocytes following molybdate-catalyzed hydrolysis.

Normal human washed erythrocytes were incubated in autologous plasma with 32P for varying periods of time. 2,3-Bisphosphoglyceric acid the major organic phosphate ester of red cells, was first isolated and purified by anion-exchange chromatography; subsequently, the C-2Pi was selectively hydrolyzed by a molybdate-catalyzed reaction. The C-2-bound Pi of 2,3-P2-glyceric acid was found to have a significantly higher specific activity than C-3 Pi. Intramolecular equilibration was not reached until the 180-min incubation. No evidence of overhydrolysis or internal randomization by the molybdate reaction was noted which was confirmed following hydrolysis of double-label 2,3-P2-glyceric acid 32P C-2, 33P C-3.

Effect of a single oral dose of oxymetholone on the metabolism of human erythrocytes.

Androgenic steroids have been shown to enhance erythrocyte 2,3-DPG production in vivo and in vitro, and to stimulate the pentose shunt oxidative reactions in vitro. Furthermore, a 3 beta- and a 17 beta-hydroxysteroid dehydrogenase have been identified in red cells. The present study was carried out to explore a cumulative effect of androgens on glycolysis and androgen reduction in human erythrocytes in vivo following a single 50 mg oral dose of 17 beta-hydroxy-2 (hydroxymethylene)-17 methyl-5 alpha-androstan-3-one (oxymetholone). The rate of erythrocyte glycolysis was measured by quantitative determination of: fructose-1,6-diphosphate (FDP); dehydroxyacetone phosphate (DAP); 2,3-diphosphoglycerate (2,3-DPG); adenosine triphosphate (ATP); and lactate. Serum and erythrocyte steroids were separated by thin layer chromatography. The reduction of 5 alpha-androstan-17 beta-ol-3-one by red cell hemolysate was measured in the presence of NADPH as an index of 3(17)beta-hydroxysteroid dehydrogenase activity. Our results show that oxymetholone administration is followed by the appearance of an unidentified steroid fraction in chromatograms of serum and erythrocytes, simultaneously with the enhancement of glycolysis and of hydroxysteroid dehydrogenase activity in erythrocytes. A direct effect of androgen on erythrocyte metabolism, which is independent of the hormone erythropoietic effect, is discussed.

Characteristics of peripheral blood monocytes in hereditary xerocytosis and spherocytosis.

Peripheral blood monocytes isolated from patients with congenital hemolytic anemia, hereditary xerocytosis and spherocytosis, demonstrated in vivo engulfment of red cell and platelet fragments. In addition, morphometric studies performed on these monocytes showed an increase in cytoplasmic/nuclear ratio as well as lysosome and phagosome volumes. The production of carbon dioxide from glucose-1-14C in abnormal monocytes was increased (15-80%) but the intracellular values of beta-glucuronidase and esterase activity were similar to control monocytes. Monocyte locomotion assessed in the presence of chemotactic stimuli was found significantly increased (73 +/- 12 monocytes/oil immersion fields vs. 46 +/- 5 for control monocytes). We concluded that the monocytes in hemolytic anemias associated with increased in vitro red cell fragmentation have some features resembling the 'stimulated' monocytes and that this alteration may be due to red blood cell fragment ingestion.