Electron Microscopic Studies on the Thyroid Gland of the Hagfish, &lt;i&gt;Eptatretus burgeri&lt;/i&gt;. (A Part of Phylogenetic Studies of the Thyroid Gland)

Fujita, Hisao; Shinkawa, Yasuhiro

doi:10.1679/aohc1950.37.277

Cited by 12 publications

(8 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The number of microvilli found on the apical surfaces of hagfish follicular cells ranged from 380 to 500 among the cells, similar to that of microvilli of mammalian follicular cells (300-400 in dogs, 400 in rats, 200-250 in swine) (Kobayashi 1973). Moreover, we occasionally observed central cilia which could not be found in the same species by transmission electron microscopy (Fujita and Shinkawa 1975).…”

Section: Discussionmentioning

confidence: 70%

“…Presumably, these inclusions correspond to dense granules, which have been demonstrated in light and transmission electron microscopic studies (Waterman and Gorbman 1963, Gabe 1971, Henderson and Gorbman 1971, Fujita and Shinkawa 1975. Presumably, these inclusions correspond to dense granules, which have been demonstrated in light and transmission electron microscopic studies (Waterman and Gorbman 1963, Gabe 1971, Henderson and Gorbman 1971, Fujita and Shinkawa 1975.…”

Section: Discussionmentioning

confidence: 81%

“…In the follicular cells of the hagfish cytoplasmic inclusion bodies having a spherical or oval shape were observed. Presumably, these inclusions correspond to dense granules, which have been demonstrated in light and transmission electron microscopic studies (Waterman and Gorbman 1963, Gabe 1971, Henderson and Gorbman 1971, Fujita and Shinkawa 1975. It is postulated that the dense granules may be intracellular storage deposits of the secretory product of the follicular cells (Gabe 1971, Henderson andGorbman 1971).…”

Section: Discussionmentioning

confidence: 92%

See 2 more Smart Citations

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

Suzuki

Kawabata

1988

Acta Zoologica

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 70%

Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 92%

See 1 more Smart Citation

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

Suzuki

Kawabata

1988

Acta Zoologica

View full text Add to dashboard Cite

show abstract

“…It is considered that the iodination of thyroglobulin takes place almost entirely in the follicle lumen especially at the periluminal region (4). The most primitive thyroid gland in the hagfish also shows similar patterns for the site of iodination of tyrosine in thyrolgobulin-equivalent protein (11). In the thyroid-homologous organ called endostyle in the larval lamprey and tunicate (Giona intestnalis), the main site of the iodination of tyrosine in thyroglobulinequivalent protein is an apical plasma membrane region and may be also in the endostylar lumen (7,9).…”

Section: Autoradiography Of 1251mentioning

confidence: 83%

“…Many researchers, using this method, showed that silver grains appear almost entirely in the follicular lumen within a few min or a few hr after the injection of 1251 into the mouse, rat, frog, and fish (2,4,5,6,11,20). In the mouse thyroid cultured in the medium containing 125I, silver grains appear only in the follicle lumen within 30 sec, and increase rapidly in number with time.…”

Section: Autoradiography Of 1251mentioning

confidence: 99%

Cytochemical aspects on the secretion mechanism of the thyroid gland.

Fujita

1981

Acta Histochem. Cytochem

Self Cite

View full text Add to dashboard Cite

OrientationIn the thyroid hormones, triiodothyronine (T3) and thyroxine (T4) are not peptides but characteristic amino acid derivatives, derived from only two molecules of iodotyrosine linked by ether bond (-o-). In all the peptide-secreting cells, the secretory granule, which originates from the rough endoplasmic reticulum and Golgi apparatus system, is released into the connective tissue space. However, formation of T3 and T4 in the thyroid requires more complicated steps. The hormones are not synthesized directly from their constituents, tyrosine and iodine in the cell, but a part of their synthetic process takes place in the extracellular lumen, called the follicle lumen. The secretory process of T3 and T4 is as follows: (i) synthesis of a large molecular glycoprotein (MW 660,000), called thyroglobulin in the follicle epithelial cell, (ii) release of thyroglobulin into the follicle lumen, (iii) iodination of the tyrosyl residues of thyroglobulin, and coupling of iodotyrosine residues to make T3 or T4 in thyroglobulin, (iv) reabsorption of thyroglobulin from the follicle lumen into the follicle epithelial cell, (v) hydrolysis of thyroglobulin for the liberation of T3 and T4, and (vi) release of T3 and T4 from the follicle epithelial cell into the connective tissue space. The present paper deals with the outline of cytochemical aspects on the secretion mechanism of the thyroid gland, except for the parafollicular cell, which secretes a peptide hormone called thyrocalcitonin. Autoradiography of 3H-amino acidThe follicle epithelial cell has to synthesize a high-molecular-weight glycoprotein, called thyroglobulin. As in other protein secretory cells, the proteinous part of thyroglobulin is synthesized at the attached ribosomes of the well developed rough endoplasmic reticulum and is stored in the cisternae of this organelle. Then the synthesized protein is transported to the Golgi apparatus, where the secretory granules, about 200 nm in diameter, arise. By the electron microscopic autoradiography of 3H-amino acid, the intracellular route for the synthesis and release of thyroglobulin has been clarified (3,6,18). In our data, the labeled amino acid first appears in the cisternae of rough endoplasmic reticulum within 15 min after the intraperitoneal injection of 3H-leucine. Then the silver grains begin to appear in the Golgi apparatus and subapical vesicles (secretary granules) after 30-45 min and in the follicle lumen after 45 min (3, 6).The proteinous part of thyroglobulin has to be bound to carbohydrate elements to become a glycorpotein. Using electron microscopic autoradiography of 3H-mannose, 3H-galactose, and 3H-fucose, the problem concerning the site of incorpo-391

show abstract

Deiodination activity in extrathyroidal tissues of the Atlantic hagfish,Myxine glutinosa

et al. 2000

View full text Add to dashboard Cite

We measured low substrate (<1 nM) thyroid hormone (TH) deiodination activities in liver, muscle, intestine, and brain microsomes of Atlantic hagfish fasted for 2 weeks and found extremely low thyroxine (T 4) outer-ring deiodination (T 4 ORD) and inner-ring deiodination (T 4 IRD) as well as 3,5,3′-triiodothyronine (T 3) IRD activities. T 3 ORD, 3′,5′-triiodothyronine (rT 3) ORD and rT 3 IRD activities were undetectable. Hagfish deiodinating pathways resembled those of teleosts in requiring a thiol cofactor (dithiothreitol, DTT) and in their inhibition by established deiodinase inhibitors and by TH analogues. However, under optimal pH and DTT conditions intestinal T 4 ORD activity exceeded that of liver about 10-fold. This contrasts with the situation in teleosts but resembles that reported recently in larval and adult lampreys, suggesting the intestine as a primary site of TH deiodination in lower craniates.

show abstract

Electron Microscopic Studies on the Thyroid Gland of the Hagfish, <i>Eptatretus burgeri</i>. (A Part of Phylogenetic Studies of the Thyroid Gland)

Cited by 12 publications

References 24 publications

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

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

Cytochemical aspects on the secretion mechanism of the thyroid gland.

Deiodination activity in extrathyroidal tissues of the Atlantic hagfish,Myxine glutinosa

Contact Info

Product

Resources

About