In order to know the effects of thyroid hormone on the bursa of Fabricius in chicken, the bursa were studied with the light microscope after administration of thyroxine(TX) or propylthiouracil(PPT).
Macroscopically, the bursa of TY-treated group showed increase in size and thickened folds, while those of the PPT-treated group decrease in size, compared with those of control group.
In the light microscopic studies, the bursa of Fabricius of the TX-treated group showed active cell-divisions in the medulla, and increased number of pyroninophilic large lymphocytes and plasma cells containing PAS positive materials in the cytoplasms. On the other hand, the bursa from PPT-treated group revealed decreased number of lymphocytes, significant increase of necrotic lymphocytes in the follicles, and the proliferation of the interfollicular connective tissues. A large number of pyroninophilic lymphocytes and plasma cells were also appeared in the spleen of the TX-treated group.
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