Summary
The fine structure of thyroids of hibernating and aroused bats, Myotis lucifugus, was observed with the electron microscope.
-
(1)
In the hibernating bat for 5 months the thyroid follicular epithelial cell is markedly attenuated and the rough endoplasmic reticulum and Golgi apparatus are very poor in development, while the mitochondria are larger and distributed throughout the cytoplasma. Intracellular colloid droplets are difficult to find. Homogeneously dense small granules suggesting primary lysosomes are numerous. Half an hour to 2 hours after injection of 100 μc of 125I, very few silver grains are recognized in a follicle lumen electron microscopic autoradiographically.
-
(2)
Half an hour to 2 hours after the intraperitoneal injection of 1 unit of thyroid stimulating hormone (TSH) into hibernating bats, several colloid droplets, many small smooth-surfaced vesicles and a few coated vesicles appear in the apical cytoplasm of the thyroid follicle epithelial cell. The small vesicles are gathered around the large droplet, and some of them are fused with it. The rough endoplasmic reticulum does not show any marked reaction. These facts suggest the possibility that the luminal colloid is reabsorbed in the form of large droplets as well as in the form of small vesicles. Dense granules (lysosomes) gathered near the colloid droplets and some of the colloid droplets themselves become heterogeneously dense. Half an hour to 2 hours after injection of 100 μc of 125I simultaneously with TSH into hibernating bats, silver grains which are markedly increased in number, as compared with those of the non-treated hibernating animal, are recognized in the follicle lumen electron microscopic autoradiographically.
-
(3)
At 2–3 hours after injection of TSH into the hibernating bat, the appearance of crystals in over half of the colloid droplets is characteristic. Each crystal consists of aggregates of numerous needle-like filaments, about 65 Å in diameter, running parallel with one another. Center to center distances between these filaments cut in longitudinal section are about 150 Å. The filaments are arranged regularly along two or three axes. These crystals are considered to be altered thyroglobulin.
-
(4)
The follicular epithelial cells of aroused bats (24° C, laboratory room in winter) from the hibernation show heterogeneity in their fine structure. Some cells seem active, and the others look inactive. In 15-day aroused bats, though most cells are flattened and the rough endoplasmic reticulum is sparse, a few cells show a fairly well developed rough endoplasmic reticulum with somewhat dilated cisternae. Large colloid droplets occur sometimes in a few cells. Lysosomal dense granules, reduced in number as compared with those of hibernating animals, are considered to originate from the Golgi apparatus. In 30 and 40-day aroused bats, the rough endoplasmic reticulum of most cells becomes more enlarged, and some follicular cells are quite similar to those of non-hibernating bats obtained in the field. In 60-day aroused bats, all the follicular epithelial cells show quite the same feature as the active thyroid cell of non-hibernating mammals.
Similar content being viewed by others
References
Bargmann, W.: Die Schilddrüse. In: Handbuch der mikroskopischen Anatomie des Menschen (W. v. Möllendorff, ed.), Bd. VI/2. Berlin: Springer 1939.
Bensley, R. R.: The thyroid gland of the opossum. Anat. Rec. 8, 431–443 (1914).
Dodgen, C. L., Blood, F. R.: Energy sources in the bat. Amer. J. Physiol. 187, 151–154 (1956).
Ekholm, R., Sjöstrand, F.: The ultrastructural organization of the mouse thyroid gland. J. Ultrastruct. Res. 1, 178–199 (1957).
—, Smed, S.: On dense bodies and droplets in the follicular cells of the guinea pig thyroid. J. Ultrastruct. Res. 16, 71–82 (1966).
Fujita, H.: Electron microscopic studies on the thyroid gland of domestic fowl, with special reference to the mode of secretion and the occurrence of a central flagellum in the follicular cell. Z. Zellforsch. 60, 615–632 (1963).
—: Thyroid gland. In: Fine structure of cells and tissues. Electron microscopic atlas. V. Endocrine Organ, Skin, eds. K. Kurosumi and H. Fujita. Tokyo: Igaku Shoin, 1968.
—: Studies on the iodine metabolism of the thyroid gland as revealed by electron microscopic autoradiography of 125I. Virchows Arch. Abt. B 2, 265–279 (1969).
—, Machino, M.: Fine structure of intramitochondrial crystals in rat thyroid follicular cell. J. Cell Biol. 23, 383–385 (1964).
—: Electron microscopic studies on the thyroid gland of a teleost, Seriola quinqueradiata. Anat. Rec. 152, 81–98 (1965).
—, Suemasa, H.: Cytological effects of TSH on the thyroid of hypophysectomized rats with and without previous administration of actinomycin D. An electron microscope study. Arch. histol. jap. 30, 45–60 (1968).
Heimann, P.: Ultrastructure of human thyroid; A study of normal thyroid, untreated and treated diffuse toxic goiter. Acta endocr. (Kbh.) 110, 1–102 (1966).
Lupulescu, A., Petrovici, A.: Ultrastructure of the thyroid gland. Basel-New York: S. Karger 1968.
Miller, T., Palade, G. E.: Lytic activities in renal protein absorption droplets. An electron microscopical cytochemical study. J. Cell Biol. 23, 519–552 (1964).
Nadler, N. J., Sarkar, S. K., Leblond, C. P.: Origin of intracellular colloid droplets in the rat thyroid. Endocrinology 71, 120–129 (1962).
—, Young, B. A., Leblond, C. P., Mitmaker, B.: Elaboration of thyroglobulin in the thyroid follicle. Endocrinology 74, 333–354 (1964).
Nunez, E. A., Gould, R. P., Hamilton, D. W., Hayward, J. S., Holt, S. J.: Seasonal changes in the fine structure of the basal granular cells of the bat thyroid. J. Cell Sci. 2, 401–410 (1967).
—, Holt, S. J.: A study of granule formation in the bat parafollicular cell. J. Cell Sci. 5, 531–559 (1969).
—: Seasonal changes in secretory granules and crystalloid inclusions of bat thyroid parafollicular cells. J. Cell Sci. 6, 821–841 (1970).
Sadler, W. W., Tyler, W. S.: Thyroidal activity in hibernating chiroptera. II. Synthesis of radio-iodinated amino acids. Acta endocr. (Kbh.) 34, 597–604 (1960).
Seljelid, R.: Endocytosis in thyroid follicle cells. II. A microinjection study of the origin of colloid droplets. J. Ultrastruct. Res. 17, 401–420 (1967a).
—: Endocytosis in thyroid follicle cells. III. An electron microscopic study of the cell surface and related structures. J. Ultrastruct. Res. 18, 1–24 (1967b).
—: Endocytosis in thyroid follicle cells. IV. On the acid phosphatase activity in thyroid follicle cells, with special reference to the quantitative aspects. J. Ultrastruct. Res. 18, 237–256 (1967c).
—, Reith, A., Nakken, K. F.: The early phase of endocytosis in rat thyroid follicle cells. Lab. Invest. 23, 595–605 (1970).
Sheldon, H., McKenzie, J. M., Nimwegan, D. van: Electron microscopic autoradiography. The localization of I125 in suppressed and thyrotropin-stimulated mouse thyroid gland. J. Cell Biol. 23, 200–205 (1964).
Stein, O., Gross, J.: Metabolism of I125 in the thyroid gland studied with electron microscopic autoradiography. Endocrinology 75, 787–798 (1964).
Vidovic, V. L., Popovic, V.: Studies on the adrenal and thyroid glands of the ground squirrel during hibernation. J. Endocrinol. 11, 125–133 (1954).
Wetzel, B. K., Spicer, S. S., Wollman, S. H.: Changes in the fine structure and acid phosphatase localization in rat thyroid cells following thyrotropin administration. J. Cell Biol. 25, 593–618 (1965).
Wissig, S. L.: The anatomy of secretion in the follicular cells of the thyroid gland. I. The fine structure of the gland in the normal rat. J. biophys. biochem. Cytol. 7, 419–432 (1960).
—: The anatomy of secretion in the follicular cells of the thyroid gland. II. The effect of acute thyrotropic hormone stimulation on the secretory apparatus. J. Cell Biol. 16, 93–117 (1963).
Wollman, S. H., Burstone, M.: Localization of esterase and acid phosphatase in granules and colloid droplets in rat thyroid epithelium. J. Cell Biol. 21, 191–201 (1964).
Yoshimura, F., Irie, M.: Licht- und elektronenmikroskopische Studie an den Krystalloiden in der Schilddrüsenzelle. Z. Zellforsch. 55, 204–219 (1961).
Author information
Authors and Affiliations
Additional information
This investigation was supported by a grant from the Dr. Henry C. Buswell and Bertha H. Buswell Research Fellowship.
On leave from the Department of Anatomy, Hiroshima University School of Medicine, Hiroshima, Japan as a Visiting Research Professor. The author wishes to express his thanks to Dr. Oliver P. Jones for giving him the opportunity to study in his laboratory and for criticism of this manuscript. The author also wishes to express his gratitude to Dr. Frank C. Kallen and Mr. Kunwar Bhatnagar for materials and advice and Mr. John Wirth and Mrs. Esther West for their technical assistance.
Rights and permissions
About this article
Cite this article
Fujita, H. Some observations on the fine structure of thyroids of hibernating and aroused bats. Z. Zellforsch. 121, 301–318 (1971). https://doi.org/10.1007/BF00337635
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00337635