Alternative RNA splicing of calcitonin/calcitonin gene-related peptide minigene transcripts in a thyroid C-cell line

Immunocytochemical study of parafollicular (C) cells of the thyroid in some wild rodents

Studies were done on 3 wild species of rodents: field voles (Microtus agrestis, Linnaeus 1761), bank voles (Clethrionomys glareolus, Schreber 1780), and forest mice (Apodemus flavicollis, Melchior 1834). Immunocytochemical reactions were used to detect calcitonin (CT), calcitonin gene-related peptide (CGRP), neuron-specific enolase (NSE), chromogranin A (CgA) in the thyroid parafollicular (C) cells in all species examined. Antisera to human CT, rat CGRP, bovine CgA, rat NSE and human NSE give probably a positive reaction in all C cells in the rodents examined. However, in the NSE determining reaction, much feebler positive C cells were observed. Individual variation in respect of shape and distribution of C cells was observed in all species. In forest mice the C cells resembled in shape the C cells previously described in mouse and rat. In field voles and bank voles the C cells were assembled into small groups more often than in forest mice. Antibodies (anti-human CT, anti-rat CGRP, anti-bovine CgA, anti-rat NSE and anti-human NSE) used by us were good markers of C cells in the thyroids of the 3 species of free-living rodents examined.

Expression of the calcitonin gene family in medullary thyroid carcinoma

The regulatory peptide calcitonin was discovered in 1962. During the last decade it has been demonstrated to be part of a gene family. Calcitonin is synthesized in the parafollicular cells (C cells) of the thyroid gland. These cells give rise to an endocrine tumor, medullary thyroid carcinoma (MTC), which is found in a sporadic and an inherited form. Calcitonin is used as a tumor marker for MTC. The calcitonin gene was demonstrated in 1981 to give rise to an alternative peptide product, alpha-CGRP, and a second gene encoding a very similar peptide, beta-CGRP, has also been identified. A third CGRP-like peptide, amylin, was identified in 1986. This article summarizes the present knowledge about gene structure, regulation of gene expression, and expression of the calcitonin gene family in MTC and in MTC-derived cell lines. The methods employed for detection of gene expression and for measurement and characterized of peptide products are described, and finally the relevance of biochemical tumor markers is discussed in relation to the new diagnostic methods for inherited MTC based on molecular biological techniques.