Studies of calcitonin cells and parathyroid gland of house shrew, Suncus murinus in response to experimental hypercalcemia.

1. Hypercalcemia was induced in S. murinus by alternate day intramuscular injections of vitamin D (25 000 IU) and by providing them 1% CaCl2 solution (prepared in tap water) for drinking. 2. After such a treatment the serum calcium values recorded a rise as compared to those of the control specimens. 3. The histological picture of the thyroid of the treated specimens reveals increased number of calcitonin cells. This observation is supported by the occurrence of mitotic figures among them. 4. Perpetual calcium challenge results in degranulation of the secretory material (calcitonin) among these cells (at 26th and 30th day of treatment). 5. It also results in degenerative changes in certain number of C cells. 6. The blood capillaries around these cells get dilated and secretory granules of C cells tend to gather at the periphery of cytoplasm and towards vascular pole. 7. The parathyroid shows atrophic changes.