title: Light- and electron-microscopical localization of calcitonin, calcitonin gene-related peptide, somatostatin and C-terminal gastrin/cholecystokinin immunoreactivities in rat thyroid.
abstract: Parafollicular C cells of the rat thyroid contain several immunoreactive peptides including calcitonin (CT), calcitonin gene-related peptide (CGRP), somatostatin and a C-terminal gastrin/CCK immunoreactive epitope as shown at the light- and electron-microscopical levels. Adult thyroid C cells are strongly immunoreactive to CT and most of the cells also react strongly with CGRP antisera and weakly with a gastrin/CCK antiserum. The latter antiserum may cross-react with CGRP. This cross-reactivity probably only occurs at very high concentrations of CGRP observed in adult thyroid C cells, but not in intrathyroidal CGRP-containing nerves, nor in early neonatal C cells. In neonatal rats, somatostatin immunoreactive C cells are numerous and most of these cells are also CT and CGRP immunoreactive. In contrast, only few C cells display somatostatin immunoreactivity in adult rat thyroids. Sequential staining experiments revealed that some thyroidal C cells simultaneously express all four types of immunoreactivity. At the electron microscopical level, all of these immunoreactivities were observed in secretory granules of C cells. Double- and triple-staining experiments, moreover, documented that some peptides are co-localized in the same granules.
authors.affiliation: Unit of Histochemistry, University Institute of Pathology, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Arias
authors.forename: L
authors.initials: L
authors.lastname: Scopsi
authors.forename: J A
authors.initials: JA
authors.lastname: Fischer
authors.forename: L I
authors.initials: LI
authors.lastname: Larsson
mesh_terms: D000818:Animals; D002116:Calcitonin / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide; D002766:Cholecystokinin / Q000378:metabolism*; D005755:Gastrins / Q000378:metabolism*; D007150:Immunohistochemistry; D009479:Neuropeptides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000378:metabolism*; D013961:Thyroid Gland / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D005755:Gastrins; D009479:Neuropeptides; D013004:Somatostatin; D002116:Calcitonin; D002766:Cholecystokinin; D015740:Calcitonin Gene-Related Peptide