Ultrastructural localization of calcitonin, somatostatin and serotonin in parafollicular cells of rat thyroid

Summary Three hormones were demonstrated in ultrathin sections of the rat thyroid using immunocytochemical methods with either a PAP complex or a protein A-gold complex as the tabel. In control rats, calcitonin was found to be present in all parafollicular cells and somatostatin in occasional cells. In rats pretreated with 5-hydroxytryptophan, serotonin was detected in all parafollicular cells as well. In serial ultrathin sections, the three hormones were seen to be localized in the same secretory granules.     

Differential changes in calcitonin,somatostatin and gastrin/cholecystokinin-like immunoreactivities in rat thyroid parafollicular cells during ontogeny

Summary Immunocytochemical quantitative studies on the development of rat thyroid calcitonin (C) cells have been performed. In neonatal rat pups up to day 6 nearly 90% of all calcitonin cells are also somatostatin immunoreactive and 45% of these cells also show immunoreactivity to a C-terminal gastrin/cholecystokinin antiserum (CCK-4-like immunoreactivity). Already at day 8 the frequency of somatostatin immunoreactive calcitonin cells has dropped to 25%, whereas half of the calcitonin cells still display CCK-4-like immunoreactivity. In adult rats, less than 1% of the calcitonin cells are somatostatin immunoreactive, whereas 90% of the calcitonin cells display CCK-4-like immunoreactivity. These data show that between day 6–8 a pronounced change in the peptide repertoire of rat thyroid C cells occur and that these cells, prior to this time, mainly contain calcitonin and somatostatin immunoreactivity and after this time mainly contain calcitonin and CCK-4-like immunoreactivity. The time course of the change in the C cell peptides is similar to that observed with changes in transitory peptides of neonatal rat pancreas and duodenum, suggesting that possible hormonal mechanisms during this period act to change the peptide repertoire of several endocrine cell types simultaneously. It is possible that many of the transitory peptides exert actions in the developing individual that are necessary for growth and differentiation. interestingly, many of these transitory peptides reappear in tumours, where theoretically they could exert similar actions.     

Differential changes in calcitonin, somatostatin and gastrin/cholecystokinin-like immunoreactivities in rat thyroid parafollicular cells during ontogeny

Immunocytochemical quantitative studies on the development of rat thyroid calcitonin (C) cells have been performed. In neonatal rat pups up to day 6 nearly 90% of all calcitonin cells are also somatostatin immunoreactive and 45% of these cells also show immunoreactivity to a C-terminal gastrin/cholecystokinin antiserum (CCK-4-like immunoreactivity). Already at day 8 the frequency of somatostatin immunoreactive calcitonin cells has dropped to 25%, whereas half of the calcitonin cells still display CCK-4-like immunoreactivity. In adult rats, less than 1% of the calcitonin cells are somatostatin immunoreactive, whereas 90% of the calcitonin cells display CCK-4-like immunoreactivity. These data show that between day 6-8 a pronounced change in the peptide repertoire of rat thyroid C cells occur and that these cells, prior to this time, mainly contain calcitonin and somatostatin immunoreactivity and after this time mainly contain calcitonin and CCK-4-like immunoreactivity. The time course of the change in the C cell peptides is similar to that observed with changes in transitory peptides of neonatal rat pancreas and duodenum, suggesting that possible hormonal mechanisms during this period act to change the peptide repertoire of several endocrine cell types simultaneously. It is possible that many of the transitory peptides exert actions in the developing individual that are necessary for growth and differentiation. Interestingly, many of these transitory peptides reappear in tumours, where theoretically they could exert similar actions.     

Ultrastructural localization of calcitonin and somatostatin in C cells of rabbit thyroid

C cells of rabbit thyroid exhibit significant differences in morphology, namely a variable nuclear structure and differences in size and osmophility of secretory granules. An examination of serial sections of these cells was made, using the immunocytochemical PAP or protein A-gold procedures. All C cells, irrespective of their morphology, were found to store both calcitonin and somatostatin in all secretory granules. The physiological role of somatostatin in calcitonin secretion by C cells is discussed.     

降钙素基因相关肽(CGRP)mRNA在大鼠淋巴细胞中的表达

最近,我们研究发现大鼠胸腺和淋巴结淋巴细胞中存在降钙素基因相关肽（ＣＧＲＰ）样免疫反应活性。应用人工合成的可特异扩增降钙素／降钙素基因相关肽基因部分片断的寡核苷酸引物,通过逆转录－多聚酶链反应（ＲＴ－ＰＣＲ）,检测在大鼠脊髓背根神经节、胸腺细胞及肠系膜淋巴结淋巴细胞中是否存在ＣＧＲＰ ｍＲＮＡ,进一步研究大鼠淋巴细胞能否合成ＣＧＲＰ。结果显示,通过ＲＴ－ＰＣＲ从脊髓背根神经节（阳性对照）、胸腺和淋     

Hybridocytochemical and immuno-ultrastructural study of calcitonin gene expression in cultured medullary carcinoma cells

The study was aimed at a morphological demonstration of calcitonin (CT) gene expression in cultured TT cells, or, more specifically, hybridocytochemical detection of CT mRNA and calcitonin gene-related peptide (CGRP) mRNA and ultrastructural localization of the two hormones. The TT cells originated from medullary carcinoma of human thyroid gland. Ultrastructural studies of TT cells demonstrated a well-developed rough endoplasmic reticulum, large Golgi apparatus and low number of secretory granules. Hybridocytochemical studies showed the presence of mRNAs for CT and CGRP in all TT cells. At the ultrastructural level, double immunolabelling demonstrated that the two hormones were always expressed together in the same secretory granules. Our results provide a significant addition to the biochemical studies performed up to now and indicate that all TT cells produce both mRNAs and both hormones in parallel.     

Localization of calcitonin and calcitonin gene-related peptide mRNAs in rat parafollicular cells by hybridocytochemistry

By use of appropriate fragments of CT DNA or a CGRP DNA and SP6 polymerase system, we produced anti-sense RNA probes labeled with biotinylated 11-UTP. The labeling and specificity of the RNA probes were confirmed using dot-blot hybridization. By use of hybridocytochemistry, CT mRNA and CGRP mRNA were localized in all parafollicular cells in control and dihydrotachysterin-pre-treated rats. We concluded that all parafollicular cells simultaneously produce both CT mRNA and CGRP mRNA, either under control conditions or after stimulation by dihydrotachysterin-induced hypercalcemia.     

Cytochemical demonstration of cholinesterase in follicle cells and parafollicular (C-) cells of the rat thyroid gland

Summary The localization of cholinesterase in rat thyroid gland has been studied light- and electron-microscopically after incubation in an acetyl-thiocholin medium.The enzyme, a pseudocholinesterase, is found in follicle cells as well as in parafollicular (C-) cells.The distribution and volume of cholinesterase-containing cells have been investigated under normal conditions by means of a point count method. The results indicate some constancy in the pattern of distribution and in volume.This work was supported by a grant (A 1/65) from the Danish State Research Foundation.     

Synthesis of calcitonin gene-related peptide (CGRP) by rat arterial endothelial cells

We investigated the protein and mRNA expression of calcitonin gene-related peptide (CGRP) in endothelial cells of the rat thoracic aorta and femoral artery. Light microscopic immunocytochemistry revealed that immunoreactivity for CGRP was preferentially located in the endothelium of both vessels. Immunoelectron microscopy showed that CGRP-immunoreactive gold particles were preferentially localized on cisterns of the rough endoplasmic reticulum and on the Weibel-Palade (WP) bodies in the endothelial cells. Prepro CGRP mRNA signals were also detected on the endothelium. Our results are the first to demonstrate that endothelial cells of both elastic and large muscular arteries synthesize CGRP and store it, in part, in WP bodies, implying that CGRP may act as an endothelium-derived relaxing factor in these vessels.     

Ontogeny and ultrastructure of somatostatin and calcitonin cells in the thyroid gland of the rat

Summary Calcitonin cells are relatively numerous in the thyroid gland of the rat. In contrast, somatostatin cells are very scarce except at the time of birth and a few days thereafter, when they are conspicuously numerous. Somatostatin cells of the thyroid gland, which are ultrastructurally similar to somatostatin cells in gut and pancreas, also contain immunoreactive calcitonin. It is not clear whether somatostatin cells in the rat thyroid gland produce calcitonin or accumulate calcitonin from the environment.     

Parafollicular cells of rabbit thyroid store both calcitonin and somatostatin and resemble gut D cells ultrastructurally

Summary Both calcitonin and somatostatin have been detected immunohistochemically in rabbit parafollicular cells; only calcitonin has been found in the same cells of the dog, guinea-pig and man. Large amounts of a peptide radioimmunochemically identical with synthetic somatostatin have been detected in extracts of rabbit thyroid. The ultrastructural and staining features of rabbit parafollicular cells differ from those of parafollicular cells in other species, while resembling in part those of somatostatin D cells scattered in the rabbit stomach.Supported in part by grants from the Italian Ministero della Pubblica Istruzione and Consiglio Nazionale delle Ricerche     

Molecular characterization of calcitonin gene-related peptide (CGRP) in a rat medullary thyroid carcinoma cell line

The rat medullary thyroid carcinoma cell line, CA-77, is known to express the calcitonin gene and the cell line has been used for characterization of procalcitonin. The present investigations concentrate on a molecular characterization of the calcitonin gene-related peptide (CGRP) expressed by a subclone of this cell line. The investigations demonstrate that this subclone produces significantly more CGRP compared to calcitonin. Gel chromatography of cell extracts demonstrates heterogeneity for both CGRP and calcitonin, but a significant amount of immunoreactivity elutes corresponding to the elution position for synthetic CGRP and calcitonin, respectively. The gel chromatogram for CGRP demonstrates four immunoreactive peaks with K_d of 0.42, 0.53, 0.68, and 0.85. The immunoreactive peak with K_d 0.42 elutes corresponding to synthetic rat CGRP. The four immunoreactive peaks were characterized by high pressure liquid chromatography followed by sequence analysis and mass spectrometry. The immunoreactive peak with K_d 0.42 was identified as rat -CGRP as was the peak with K_d 0.53. The peak with K_d 0.68 was identified as 19–37 rat -CGRP and the peak with K_d 0.85 as 28–37 rat -CGRP. In summary, we find that the CA-77 cell line expresses large quantities of normally processed amidated -CGRP and specific fragments thereof. However, the cell line does not express detectable levels of rat β-CGRP. The findings indicate that the CA-77 cell line can be useful for studies of calcitonin/CGRP gene expression.     

神经肽Y、钙基因相关肽和P物质在甲状腺中的分布及其在甲亢状态下的变化(英文)

以往的研究表明,甲状腺中分布有肽能神经,包括神经肽Y(NPY)能神经、P物质(SP)能神经和脑肠肽(VIP)能神经.这些神经纤维的终末与血管和甲状腺的滤泡接触.一般认为,甲状腺的功能活动主要受下丘脑-垂体-甲状腺轴的调节,有关神经肽的调节,尤其是在甲亢状态下的调节尚不清楚.本研究以SD大鼠为实验动物,通过T4注射建立甲亢动物模型.使用免疫组化技术对NPY、CGRP和SP 在实验与对照动物的分布进行形态学研究,使用放射免疫测定技术对模型动物与对照动物甲状腺中的NPY、CGRP和SP进行定量研究.免疫组化技术发现NPY阳性神经纤维密集环绕小血管,其末端与血管内皮紧密联系,一些NPY阳性神经走行于滤泡间的结缔组织中,其末端与滤泡上皮接触;有SP阳性神经纤维走行于滤泡间的结缔组织中,其末端与滤泡上皮接触;CGRP阳性细胞分布于滤泡间的结缔组织中,或滤泡上皮细胞之间.放射免疫测定表明甲亢大鼠NPY、SP水平高于对照大鼠,CGRP水平低于对照大鼠.结果表明,在甲亢状态下,机体通过血管收缩介质NPY、SP的增多与血管舒张介质CGRP的减少,控制甲状腺素进入血液循环,这是机体在病理过程中的自稳机制之一.     

Light- and electron-microscopical localization of calcitonin,calcitonin gene-related peptide,somatostatin and C-terminal gastrin/cholecystokinin immunoreactivities in rat thyroid

Summary 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.     

Light- and electron-microscopical localization of calcitonin, calcitonin gene-related peptide, somatostatin and C-terminal gastrin/cholecystokinin immunoreactivities in rat thyroid

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.