Correlation between the mean corpuscular volume and reticulocytosis in phenylhydrazine anemia in swine.

O NE OF THE causes of an increase in mean corpuscular size is a pronounced reticulocytosis.’#{176} The increase in the volume of the red blood cells due to this cause is usually a temporary finding which follows a sudden loss of blood, a hemolytic crisis, or any reaction which acutely stimulates the hematopoietic system. During treatment of pernicious anemia with specific therapy, it is not unusual to find in conjunction with the reticulocyte response a transient increase in the degree of macrocytosis as measured by the mean corpuscular volume. When a macrocytic blood picture is associated with a reticulocytosis, it is often difficult to evaluate to what extent the larger size of the reticulocyte contributes to the mean corpuscular volume. This problem was encountered in the interpretation of hematologic data gathered during previous studies with swine at the Naval Medical Research Institute, Bethesda, Maryland. The present investigation was undertaken to study the correlation between the increased percentage of reticulocytes produced by phenylhydrazine hydrochloride and the mean corpuscular volume in swine under controlled conditions. Phenylhydrazine has been used by numerous workers to produce both experi-