Anti-sickling activity of nitrosoureas

Incubation at physiological conditions of erythrocytes from a person bearing the sickle-cell trait with 1-methyl-1-nitrosourea, 1,3-bis-(2-chloroethyl)-1-nitrosourea, or 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea prevented sickling of the cells upon subsequent treatment of the cells with sodium metabisulfite. In these experiments these compounds were more effective than potassium cyanate as inhibitors of sickling. It is assumed that the inhibition results from the carbamoylation of the hemoglobin S by the isocyanic acid or the isocyanates derived from the nitrosoureas.