A Scanning Electron Microscopic Study on the Thyroid Follicle of the Hagfish Eptatretus burgeri

Abstract

Suzuki, S. and Kawabata, I. 1988. a scanning electron microscopic study on the thyroid follicle of the hagfish Eptatretus burgeri. Japan.)-Acta zool. (Stockh.) 69, 253-258.The external form of the follicles was mostly spherical or oval and the large oval follicles reached more than 300 X 180 pm in size. Cytoplasmic inclusions of various sizes were observed in the follicular epithelium. Follicles were composed of hexagonal epithelial cells, and on the apical surface of the cells many microvilli were found (380-500 microvilli per cell) with globular or amorphic cytoplasmic protrusions. In a few cells a central cilium was also observed. From these results a relationship between thyroid structure and function in the hagfish is discussed.

Ultrastructural studies of cilia formation during thyroid gland differentiation in grass snake embryos

“…Cilia were frequently found in the ultrathin sections of the differentiating thyrocytes in the grass snake at developmental stages IV-VII and IX-X and they were similar in morphology to those described in many previous ultrastructural studies of a developing (Hilfer, 1979;Remy et al, 1980Chan, 1983Martin et al, 1988) and an adult thyroid gland (Muramoto, 1964;French and Hodges, 1977;Suzuki and Kawabata, 1988). Cilia were found in post-mitotic thyrocytes.…”

“…These structures have not been described in thyrocytes in other vertebrate species. It should also be emphasised that no ciliary appendages have been described in the thyrocytes of fish (Fujita and Machino, 1965;Fujita and Honma, 1966;Suzuki and Kawabata, 1988), salamanders (Larsen, 1968), birds (Fujita and Machino, 1961;Fujita, 1963;Muramoto, 1964) or dogs (Tashiro and Sugiyama, 1964;Nunez and Gershon, 1976).…”

“…Eukaryotic cilia mediate a variety of functions that are found in many cells of differentiating and fully differentiated tissues (Alieva and Vorobjev, 2004;Gerdes et al, 2009;Plotnikova et al, 2009;Satir et al, 2010;Vincensini et al, 2011). Ciliated cells have been reported in the thyroid of many embryos and adult vertebrate species such as fish (Cowdry, 1921;Fujita and Machino, 1965;Fujita and Honma, 1966;Suzuki and Kawabata, 1988), amphibians (Coleman et al, 1968;Larsen, 1968;Setoguti, 1973;Kracht and Weber, 1978), birds (Fujita, 1963;Muramoto, 1964), dogs (Tashiro and Sugiyama, 1964;Nunez and Gershon, 1976), and humans (Zimmermann, 1898;Sobrinho-Simoes and Johannessen, 1981;Chan, 1983;Martin et al, 1988). Knowledge about the ciliogenesis in thyrocytes is lacking because this process has not been previously studied in thyrocytes of vertebrate E-mail address: weronika.rupik@us.edu.pl species.…”

Gross anatomy of the Pacific hagfish, Eptatretus burgeri, with special reference to the coelomic viscera

“…Electron microscopic analyses have revealed the presence of dense granules in the thyroid follicular epithelial cells of hagfishes, which are thought to contain iodine (Fujita, 1975; Fujita & Shinkawa, 1975; Henderson & Gorbman, 1971; Suzuki, 1985). Also, numerous microvilli are present on the apical membrane on the medial side of the follicular structure of thyroid follicular epithelial cells (Suzuki & Kawabata, 1988). These observations indicate that the thyroid follicles of hagfish do not differ significantly from those of other vertebrates in terms of histology.…”

Gross anatomy of the Pacific hagfish,Eptatretus burgeri, with special reference to the coelomic viscera

“…Electron microscopic analyses have revealed the presence of dense granules in the thyroid follicular epithelial cells of hagfishes, which are thought to contain iodine (Henderson & Gorbman, 1971; Fujita, 1975; Fujita & Shinkawa, 1975; Suzuki, 1985). Also, numerous microvilli are present on the apical membrane on the medial side of the follicular structure of thyroid follicular epithelial cells [> Also, numerous microvilli are present on the apical (luminal) membrane of thyroid follicular epithelial cells] (Suzuki and Kawabata, 1988). These observations indicate that the thyroid follicles of hagfish do not differ significantly from those of other vertebrates in terms of histology.…”