Effect of phenylhydrazine on delta-aminolevulinic acid dehydratase in red blood cells.

Delta-aminolevulinic acid dehydratase activity was measured in the blood of rats poisoned by successive injections of phenylhydrazine (1 ml, 35 mmol). After 5 days of successive injections, more than 90% of the circulating blood cells consisted of reticulocytes and the enzyme activity also increased successively and reached a maximum corresponding to the number of reticulocytes. Thus delta-aminolevulinic acid dehydratase activity measured in the peripheral blood is mainly due to the percentage of circulating reticulocytes.