American Journal of Clinical Nutrition, Vol 3, 56-63, Copyright © 1955 by The American Society for Clinical Nutrition, Inc.

Antimetabolites and Antibiotics as Tools for Research on Blood Formation

¹ From the Nutrition and Physiology Section, American Cyanamid Company, Research Division, Lederle Laboratories, Pearl River, N. Y.

(1) Folic acid antagonists are useful in the study of hemopoiesis in experimental animals.

(2) Their use in studying blood formation in patients is limited by the toxicity of aminopterin and by the fact that x-methyl folic acid has no apparent effect on human subjects.

(3) The use of the folic acid antagonists has established the role of folic acid in blood formation (a) in species which do not readily develop a dietary deficiency of folic acid such as dogs and pigs, (b) in other species which are subject to this dietary deficiency, such as rats and chicks, because the antagonists may be used to exaggerate the deficiency and to establish its reversibility. (4) Studies with the folic acid antagonists in bacteria have illuminated the role of folic acid in biochemistry and hence in hemopoiesis.

It appears that certain antibiotics may have a beneficial effect on hemopoiesis. This effect is associated with changes which the antibiotics produce in the intestinal bacteria. Among the possible changes are: (1) an increase in the production of substances in the folic acid group including citrovorum factor; (2) certain bacteria may destroy vitamin B₁₂ and this destructive effect may be lessened by administering antibiotics; (3) there is some evidence that the intestinal bacteria may produce deleterious substances which cause anemia, and that the production of these substances is suppressed by antibiotics.

The antianemic effects of antibiotics are irregular, due perhaps to inherent variations in the types and numbers of bacteria in the intestinal tract of the experimental host.