Hexavalent Chromium Toxicity in Pituitary and Thyroid Glands

Hexavalent chromium as K2Cr2O7 (60mg/kgb.w) was administered intraperitoneally to male Sprague Dawley rats. In the thyroid gland, chromium concentration decreased significantly (P<0.01) as compared to the control tissue. Serum FT3 and FT4 levels decreased significantly (P<0.01 and P<0.001 respectively), while serum TSH concentration increased significantly (P< 0.01) than the control. Histologically, in the pituitary gland, hypertrophy was evident in the anterior pituitary gland hypertrophied, the cellular density (number of cells/0.021mm) decreased significantly (P<0.001) and the cellular diameter increased significantly (P<0.001). In the thyroid gland, follicle number increased significantly (P<0.001) when compared to control. However, follicular size showed a significant decrease (P<0.001). The follicles were scattered and aggregated abnormally to form small groups making large interfollicular spaces due to the disruption of the connective tissue. The height of epithelial cells also increased. The present study demonstrates that chromium in hexavalent form causes both structural and functional disturbance to the pituitary and thyroid glands and is therefore potentially toxic to these tissues.