Author/Editor		Kališnik, M; Zorc-Pleskovič, R; Pajer, Z; Pavlin, K
Title		The effect of chronic hypercalcemia or hypocalcemia on the follicular and parafollicular cells in rat thyroid gland
Type		članek
Source		Am J Anat
Vol. and No.		Letnik 189, št. 3
Publication year		1990
Volume		str. 201-6
Language		eng
Abstract		In three experiments of 30 weeks' duration, 93 adult female Wistar rats received controlled amounts of calcium with food and water, to produce a state of either hypercalcemia or hypocalcemia. A systematic stereological analysis of the thyroid glands and a radioimmunological analysis of thyroxine, triiodothyronine, and thyrotropine were performed. In the hypercalcemic rats, a reactive hyperplasia of the parafollicular cells was established; this was accompanied by morphological and biochemical signs of hyperfunction of the follicular cells, despite a reduced central stimulation by thyrotropin. In the hypocalcemic animals, no quantitative morphological changes in the parafollicular cells were observed; however, morphological and biochemical signs of hypofunction of the follicular cells were obvious, despite stronger central stimulation by thyrotropin. It is concluded that the extrinsic regulation of follicular cells by the blood calcium level is stronger than the intrinsic regulation by hypothalamo-hypophyseal hormones.
Descriptors		HYPERCALCEMIA HYPOCALCEMIA THYROID GLAND CALCIUM CHRONIC DISEASE HYPERCALCEMIA HYPOCALCEMIA RADIOIMMUNOASSAY RATS RATS, INBRED STRAINS THYROID GLAND THYROTROPIN THYROXINE TRIIODOTHYRONINE