Experimental Carcinogenesis in the Rat Thyroid Follicular and C Cells

Triggs, Stella M.; Williams, E. D.

doi:10.1530/acta.0.0850084

Cited by 29 publications

(8 citation statements)

References 7 publications

(7 reference statements)

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“…A previous similar experiment showed a significant increase in incidence of C cell tumours after irradiation (Triggs & Williams 1977). Our results are interpreted as being in agreement with this finding, with the additional feature that the 10 uCi dose in the current experi¬ ment led not only to a very great reduction in C cell number in the first few months after radiation, but also to a loss in regenerative capacity, presumably because of sterilization of the cells by this radiation dosage (Thurston & Williams 1981).…”

Section: Discussionsupporting

confidence: 91%

“…Whilst it is known that the C cells respond directly to raised serum calcium levels by the secretion of calcitonin (Copp 1970), previous work from this laboratory has shown that variations in dietary calcium did not significantly influence the inci¬ dence of C cell tumours, although serum calcium levels were significantly raised (Triggs & Williams 1977). These authors used a combination of phy¬ siological stress and radiation, known to cause tumours in other endocrine glands (Furth 1953) and in the follicular cells of the thyroid (Doniach 1958).…”

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confidence: 86%

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Experimental induction of C cell tumours in thyroid by increased dietary content of vitamin D3

Thurston

Williams

1982

Acta Endocrinologica

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Neonatal Wistar rats were given either 0, 5 or 10 \g=m\Ci 131I within 24 h of birth. Following weaning, they were fed a diet high, normal or deficient in vitamin D, for up to 2 years. Animals were sacrificed at approximately 3 monthly intervals, and serial sections of thyroid scanned for C cell tumours following calcitonin localization.Plasma calcium levels were also measured, and all results statistically analyzed. As expected, those animals given the high vitamin D had significantly raised calcium levels over those on a normal D diet, whilst those given a low D diet had lower calcium levels than normal.Analysis of the incidence of C cell tumours showed that those given a high D diet had significantly more C cell tumours, whilst those on a low D diet had significantly fewer than normal. Radiation dose also influenced C cell tumour incidence.There was a significant relationship between the vitamin D content of the diet and the incidence of C cell tumours, with those animals on a high D diet having the largest number of tumours. It is suggested that vitamin D or its metabolites may directly promote C cell growth, and that the high incidence of C cell tumours in the normal laboratory rat reflects the artificially high vitamin D content of the laboratory rat diet. The dietary vitamin D content may also be relevant to the variation in geogra-

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Section: Discussionsupporting

confidence: 91%

mentioning

confidence: 86%

Experimental induction of C cell tumours in thyroid by increased dietary content of vitamin D3

Thurston

Williams

1982

Acta Endocrinologica

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“…Neither consistent changes in total blood calcium and phosphorus nor bone lesions have been reported in rats with calcitonin-secreting C-cell neoplasms. Triggs and Williams (62) reported that radiation (5 or 10 pCi I3'I) increased the incidence of thyroid C-cell (as well as follicular cell) tumors in Wistar rats but that high dietary calcium intake (2,000 mdlOO g) did not further increase the incidence of C-cell tumors in irradiated rats. Further studies by Thurston and Williams (61) found that irradiated rats receiving diets high in vitamin D that developed hypercalcemia had a higher incidence of C-cell tumors than rats fed diets adequate or deficient in vitamin D. Stoll et a1 (59) reported that the antithyroid drug, thiamazole, can result in proliferative lesions (hyperplasia and adenoma) in thyroid C-as well as follicular cells in rats.…”

Section: Fig 34-c-cell Adenoma (C) In a Thyroid Lobe From Anmentioning

confidence: 99%

The Effects of Xenobiotics on the Structure and Function of Thyroid Follicular and C-Cells

1989

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The mammalian thyroid gland is composed of 2 distinct endocrine cell populations concerned with the synthesis of 2 different classes of hormones. Follicular cells secrete the metabolically active iodothyronines whereas the C-(parafollicular) cells are concerned with the production ofcalcitonin, a hormone that influences blood levels of calcium and phosphorus, and bone cell metabolism. The synthesis of metabolic thyroid hormones is different than in other endocrine glands because the final assembly of hormone occurs within the follicular lumen. This extracellular synthesis of thyroid hormones is made possible by thyroglobulin, a glycoprotein synthesized by follicular cells. The secretion of thyroid hormones under the influence of pituitary thyrotrophin (TSH) from stores in the luminal colloid is initiated by elongation of microvilli and formation of pseudopods. FD&C Red No. 3 is a tetraiodinated derivative of fluorescein which in lifetime studies increases the incidence of thyroid follicular cell adenomas in male Sprague-Dawley rats. The striking changes in circulating levels of thyroid hormones and morphologic evidence of follicular cell stimulation are the result of alterations in the peripheral metabolism of thyroxine. An inhibition by FD&C Red No. 3 of 5'-deiodinase in the liver and kidney would explain the lower serum triiodothyronine (T,) levels. The pituitary, sensing the lowered circulating levels of T,, increased the secretion of thyroid stimulating hormone which resulted in the morphologic evidence of follicular cell stimulation in the long-term studies. Other xenobiotics increase the incidence of thyroid tumors in rodents by a direct effect on the thyroid gland to disrupt 1 of 3 or more possible steps in the biosynthesis of thyroid hormones. Physiologic perturbations alone, such as iodine deficiency or partial thyroidectomy, can disrupt thyroid hormone economy in rodents and, if sustained, increase the development of thyroid tumors. The wide variety of drugs, chemicals, and physiologic perturbations which increase thyroid tumor development appear to act through a secondary (indirect) mechanism to promote tumor development by causing a long-standing hypersecretion of thyroid stimulating hormone. Nodular and/or diffuse hyperplasia of C-cells occurs with advancing age in many strains of laboratory rats and in response to long-term hypercalcemia in certain animal species and human beings. Focal or diffuse hyperplasia often precedes the development of C-cell neoplasms. Radiation and the feeding of diets high in vitamin D resulting in hypercalcemia have been reported to increase the incidence of C-cell tumors in rats.

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“…Thyrotropin has been reported to stimulate C cell growth as well as follicular cell proliferation in animals (26). TRIGGS and WILLIAMS showed that radiation exposure has induced neoplasia in the two cell types in rats (27). Unfortunately, we did not come across any literature referring to laser and carcinogenesis in the thyroid gland.…”

Section: Discussionmentioning

confidence: 88%

Does Percutaneous Thyroid Laser Ablation Induce Mixed Papillary and Medullary Thyroid Carcinoma ?

Ergül

Gozetlik

2010

Acta Chirurgica Belgica

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Mixed medullary-papillary carcinomas are very rare and still not listed in the WHO classification (1988). The rarity of the co-existence of medullary and papillary carcinoma suggests that these cases represent mere coincidence. Some studies have shown that radiation exposure has induced neoplasia in the two cell types in rats. But we still have limited information about the carcinogenetic effect of laser ablation on the thyroid gland. This report describes the first case of thyroid carcinoma that demonstrated both medullary carcinoma and papillary components in the thyroid, which might occur due to percutaneous thyroid laser ablation.

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Experimental Carcinogenesis in the Rat Thyroid Follicular and C Cells

Cited by 29 publications

References 7 publications

Experimental induction of C cell tumours in thyroid by increased dietary content of vitamin D3

Experimental induction of C cell tumours in thyroid by increased dietary content of vitamin D3

The Effects of Xenobiotics on the Structure and Function of Thyroid Follicular and C-Cells

Does Percutaneous Thyroid Laser Ablation Induce Mixed Papillary and Medullary Thyroid Carcinoma ?

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