title: Alteration of parafollicular (C) cells activity in the experimental model of hypothyroidism in rats.
abstract: Our previous study has shown the alteration of C cells activity in rats with experimental model of hyperthyroidism. The aim of the present study was the evaluation of parafollicular cells activity in rats with hypothyroidism evoked by propylthiouracil (PTU) given in drinking water over 21 days. Histological, ultrastructural and immunocytochemical studies using specific antibodies against calcitonin and CGRP were performed on thyroid glands taken from experimental and control groups of rats. Moreover, in all animals the calcitonin plasma levels were evaluated by radioimmunoassay. After chronic administration of PTU, thyroid image showed predominant microfollicular hyperplasia and attenuated density of parafollicular cells. The intensity of immunocytochemical reactions for CT and CGRP were weaker in the majority of C cells in comparison to the control rats, in which strong immunocytochemical reaction was observed. Examination in the electron microscope reveals the features of hypoactivity both in follicular and parafollicular cells, in which the quantity and electron density of secretory granules were smaller in comparison to the control group. These microscopic changes were accompanied by a significant decrease of calcitonin plasma concentration. Alteration of C cells activity in the experimental model of hypothyroidism, accompanied by microfollicular hypertrophy, may point to the mutual cooperation between parafollicular and follicular cells.
authors.affiliation: Department of General and Experimental Pathology, Medical University of Białystok, Poland. rzbucki@wp.pl
authors.forename: Robert Lukasz
authors.initials: RL
authors.lastname: Zbucki
authors.forename: Maria Malgorzata
authors.initials: MM
authors.lastname: Winnicka
authors.forename: Boguslaw
authors.initials: B
authors.lastname: Sawicki
authors.forename: Beata
authors.initials: B
authors.lastname: Szynaka
authors.forename: Anna
authors.initials: A
authors.lastname: Andrzejewska
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Puchalski
mesh_terms: D000818:Animals; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D007037:Hypothyroidism / Q000139:chemically induced / Q000473:pathology*; D008297:Male; D011441:Propylthiouracil / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000166:cytology / Q000473:pathology* / Q000648:ultrastructure
chemical_list: D011441:Propylthiouracil; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide