title: Calcitonin gene-related peptide (CGRP) - microadenomas of the thyroid gland induced by cadmium toxicity. Experimental study.
abstract: OBJECTIVE
  The objective of our study was to make morphological and functional analysis of thyroid C cells in rats chronically exposed to cadmium (Cd).
  
  
  METHODS
  The study was carried out on female albino Wistar rats (n=22, age=35-37 days, body mass 120-140 g), divided in control (n=11) and experimental group (n=11). The rats of the experimental group were treated with 15 mg/kg Cd dissolved (as CdCl(2)) in drinking water. The animals were sacrificed 3 months later. The thyroid glands were removed and macroscopic, histological and immunocytochemical examinations were done. Monoclonal antibodies for chromogranin A (Chr A), neuron specific enolase (NSE), calcitonin (CT), somatostatin (SST) and calcitonin gene related peptide (CGRP) were used for immunocytochemical examinations.
  
  
  RESULTS
  No pathological changes were found in parafollicular cells of the animals of the control group. All the animals of the experimental group showed bilateral diffuse C cell hyperplasia, mostly in the middle and upper thirds of the lobes. Strong immunoreactivity was present to all tested polypeptides (Chr A, CT, NSE, CGRP and SST). In 5 (45%) of the animals of the experimental group, C cell microadenomas were exclusively made of CGRP-secreting cells.
  
  
  CONCLUSIONS
  Chronic Cd exposure causes preneoplastic changes and functional differentiation of parafollicular cells of the thyroid gland, the first cell type being present in the area of diffuse hyperplasia, and the other C cell type being the constituent of microadenomas secreting CGRP exclusively. The results of this study indicate that chronic Cd exposure disturbs the structure and function of C cells of the thyroid gland.
authors.affiliation: Institute for Pathology, Faculty of Medicine University of Kragujevac, Kragujevac, Serbia. sjancic@medf.kg.ac.rs
authors.forename: S
authors.initials: S
authors.lastname: Jancic
authors.forename: V
authors.initials: V
authors.lastname: Bojanic
authors.forename: G
authors.initials: G
authors.lastname: Rancic
authors.forename: I
authors.initials: I
authors.lastname: Joksimovic
authors.forename: N
authors.initials: N
authors.lastname: Jancic
authors.forename: M
authors.initials: M
authors.lastname: Zindovic
authors.forename: V
authors.initials: V
authors.lastname: Stankovic
mesh_terms: D000236:Adenoma / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D019256:Cadmium Chloride / Q000633:toxicity*; D002116:Calcitonin / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D053379:Chromogranin A / Q000378:metabolism; D005260:Female; D007124:Immunoenzyme Techniques; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D053379:Chromogranin A; C506153:chromogranin A, rat; D013004:Somatostatin; D002116:Calcitonin; D010751:Phosphopyruvate Hydratase; D019256:Cadmium Chloride; D015740:Calcitonin Gene-Related Peptide