Response of hamster thyroid light cells to plasma calcium

Abstract

Light cells in the hamster thyroid gland were examined by electron microscopy and histochemical methods in control, hypercalcemic and hypocalcemic animals. Elevation of plasma calcium levels stimulated a marked depletion of light cell granules as detected by electron microscopy and silver impregnation. In the hypercalcemic state the size and number of light cells did not differ from that of control animals. Hypocalcemic hamsters showed a significant increase in light cell numbers with marked hypertrophy and hyperplasia of this cell type. These observations support the view that the light cell in the hamster thyroid is associated with thyrocalcitonin secretion.

Toxicological impacts of a botanical pesticide, azadirachtin on corpuscles of Stannius of stinging catfish, Heteropneustes fossilis

“…Asterisk indicates significant differences (P \ 0.05) from control positive granules in CS has been noticed earlier in response to experimentally induced hypocalcemia in fishes kept in ambient acalcic freshwater (Tiwari 1993;Singh and Srivastav Ajai 1996). Similar accumulation of secretory granules in the calcitonin cells (responsible for the secretion of a hypocalcemic factor-CT) of mammals has also been noticed in response to hypocalcemia (Biddulph and Maibenco 1972;Swarup et al 1980).…”

Calcitonin cells and unusual follicles of the thyroid of the Indian grey mongoose, <i>Herpestes edwardsi</i> (Geoffroy)

“…In the rabbit those with an oval shape are in a parafollicular position, whereas the elongated ones occupy a perifollicular (as surrounding element of the follicle) position [Kameda, 1971 b]. In the hamster some of these cells occupy an epifollicular position while others are wedged in between follicular cells [Biddulph and Maibenco, 1972]. In H. edwardsi calcitonin cells occur in intraepithelial, parafollicular and epifollicular position.…”

“…This is in agreement with the observation of Kameda [1968Kameda [ in dog, 1971b in rabbit, mice and cat], Kameda states that the calcitonin cells show a tendency to concentrate around the parathyroid IV in the dog [Kameda, 1971a]; parathyroid IV and thymus IV, or around ciliated cysts in the rabbit, mouse and cat [Kameda, 1971 b]. Later, in the hamster, these cells are reported to be consistently located within a small region of each thyroid lobe adjacent to the laterally located parathyroid gland [Biddulph and Maibenco, 1972]. But in II.…”

Alterations in the Corpuscles of Stannius of Euphorbia royleana Treated Catfish, Heteropneustes fossilis

“…In mammals, accumulation of secretory granules in the calcitonin cells (responsible for the secretion of a hypocalcemic factor-CT) has also been noticed in response to hypocalcemia [36][37][38][39].…”