418 4. ALLOXAN 



fall in erythrocyte count and hemoglobin (Merlini, 1951; Kaito et al., 

 1954). Progressive hemolysis in vitro is produced by 0.21-56 mM alloxan, 

 with probable formation of methemoglobin above 1.2 mM (Robuschi, 

 1948). Tocopherol antagonizes the hemolytic action in vivo (Gyorgy and 

 Rose, 1949). Erythrocytes from vitamin E-deficient animals are lysed 

 much more readily than cells from normal animals. Dialurate or a product 

 formed from dialurate, rather than alloxan, was thought to be the hemo- 

 lytic agent. Maske and Wolff (1953) believe that Zn++ is possibly involved 

 in both the hemolysis and the damage by alloxan to the /5-cells, and that 

 the mechanisms involved in these two apparently different actions may 

 be similar. Leucocytic phagocytosis is quite potently depressed by alloxan, 

 effects being observed at concentrations as low as 0.035 niM (Kohler et 

 al, 1951). 



EFFECTS ON CELL GROWTH AND PROLIFERATION 



Any effects observed on growth must be exerted during the initial several 

 minutes of contact with alloxan. Hence, presumably only irreversible 

 changes produced in the cells, i. e., those manifesting themselves by a sup- 

 pression of growth later, would be detected. Most culture media for in vitro 

 study contain numerous substances capable of reacting with alloxan and 

 protecting the cells. Generally speaking, alloxan has not proved to be a 

 very effective growth inhibitor. Cultures of human' gingival fibroblasts 

 are not affected by 1.4 milf alloxan during 4 days of observation (Shafer, 

 1961). The growth of E. coli is not inhibited by 0.7 mM alloxan (Zamenhof 

 and Griboff, 1954). Alloxan can inactivate encephalomyocarditis virus in 

 vitro but has no effect on the proliferation in vivo (Weinstein et al., 1957). 

 Alloxan and its metal chelates are not antitubercular in mice (Foye et 

 al., 1959). Indeed, the only positive results reported on microorganisms 

 seem to be those of Laskowski et al. (1951, 1954), who found that alloxan 

 in subdiabetogenic doses is very effective in preventing the development of 

 bartonellosis in mice and rats, being as successful as the arsenicals. 



The early embryonic development of Triton alpestris is slowed by 7 mM 

 alloxan, neurulation being abnormal and the neural plate asymmetrical 

 (Gruber, 1962). The mitotic frequency is reduced, there are chromosomal 

 abnormalities, and spindle formation appears to be disturbed. The most 

 actively proliferating and differentiating cells, as in the dorsal lip, are most 

 affected, and a high proportion become necrotic. Alloxan was classified 

 as a spindle-toxic agent. 



The anemia discussed in the previous section is initially due to hemol- 

 ysis, but there is also a depression of hematopoiesis for several days, as 

 shown by a decline in nucleated erythrocytes in the myelogram, a defi.- 

 nite granulocytosis, and an elevation in lymphocytes (Baiardi, 1955). Al- 



