ABSTRACT
The cells of the myelo id, lymphoid , and erythroid lineage s of the bone marrow were quantified in rats with hypo and hyperthyroidism. Fifteen Wistar rats were divided into three groups: hypothyroid (n=5), hyperthyroid (n=5) , and control (n=5). Three months after the onset of the treatment s, euthanasia was performed . Bone marrow was aspirated from femurs of each animal to perform smear s that were stained with Quick Panoptic. T he percentage s of rubroblast, prorubrocyte, metarubrocyte, myeloblast, promyelocytes, metamyelocytes, myel ocytes, segmented, eosinophils, basophils, lymphocytes, plasma cells and monocytes in were determined a total of 500 cells. The bone marrow of animals with hypothyroidism had hypoplasia. The myeloid:erythroid ratio was higher in animals with thyroid dysfun ction. In hypo and hyperthyroidism, there was a significant reduction of the percentage of rubrocyte, metarubrocyte , and lymphocytes and increase of myelocytes and segmented cells. In hypothyroidism, there was a significant increase in the percentage of me tamyelocytes. It is c oncluded that both hypo and hyperfunction of thyroid increase the myeloid:erythroid ratio by increasing the number of cells of the myeloid lineage and reducing the cells of the erythroid lineage.