BETA-CAROTENE INCREASES MONOCYTE NUMBERS IN PERIPHERAL RAT-BLOOD

The purpose of this study was to determine changes in leukocyte number s in peripheral rat blood after varying dietary beta-carotene intake. Thirty male weanling Sprague-Dawley rats were fed ad libitum a vitamin A deficient defined nutrient chow, adequate in all other nutrients. R ats were randomly placed in a group with beta-carotene added to the ch ow as the vitamin A source. Group 1 was completely deficient, Group 2 had 1 mu g beta-caretene/g chow, the control group, and Group 3 receiv ed 25 mu g beta-carotene/g chow. Before beginning the experimental die ts and after two weeks, a blood sample was taken from the tail vein fo r a differential white blood cell count. Animals were sacrificed by ce rvical dislocation, and the spleen and thymus were removed and weighed . There was a statistically significant increase in monocyte numbers i n Group 3, and a positive correlation between beta-carotene intake and monocyte numbers. Beta-carotene may affect monocyte numbers, a potent ial mechanism of action in cancer prevention.