Control of the pars intermedia of the lizard, Anolis carolinensis
Tóm tắt
The ultrastructure of the intermediate lobe of the hypophysis was studied in Anolis carolinensis with the use of a threefold aldehyde fixative. Lizards with a brown skin were selected. The possibility of two types of secretory cells is discussed; neither cell type is innervated. Type I cells are rarely found and contain dense granules approximately 0.3 μm in diameter; Type II cells vary widely in secretory activity. Most of the Type II cells contain a large number of dense secretory granules (up to about 1.3 μm in diameter) almost filling the cytoplasm. Rough endoplasmic reticulum (RER), Golgi apparatus and mitochondria are poorly developed. Only some of these cells show signs suggesting a high secretory activity, namely a well developed RER, Golgi apparatus and numerous mitochondria. In these cells the RER sometimes forms large intracisternal droplets (up to 7 μm in diameter). Two of the animals exhibited a more uniform, high secretory activity. Large (about 2 μm in diameter), pale vacuoles, probably of extracellular character, were found mostly in the vicinity of the perivascular septum. Their role in the release of MSH is discussed. The present data, which are discussed with reference to earlier findings (Forbes, 1972), form the morphological basis for an experimental study on regulation of MSH release (Larsson et al., 1979).
Tài liệu tham khảo
Davis, M.D., Hadley, Mac E.: Hypothalamic control of pars intermedia melanophore stimulating hormone (MSH) secretion. In: Hypothalamic Hormones — Chemistry, Physiology, and Clinical Applications. (Proceedings of the 2nd European Colloquium on Hypothalamic Hormones, Tübingen 1976) (Gupta and Voelter, eds.) pp. 395–401. Weinheim: Verlag Chemie 1978
Ferray, L.: Le lobe intermédiaire chez la couleuvre à collier: Tropidonotus natrix (L.). Etude histologique et ultrastructurale. Z. Anat. Entwickl.Gesch. 145, 269–282 (1974)
Forbes, M.S.: Observations on the fine structure of the pars intermedia in the lizard, Anolis carolinensis. Gen. Comp. Endocrinol. 18, 146–161 (1972)
Hadley, Mac E., Goldman, J.M.: Physiological color changes in reptiles. Am. Zoologist 9, 489–504 (1969)
Hogben, L.T., Mirvish, L.: The pigmentary effector system. V. The nervous control of excitement pallor in reptiles. J. Exp. Biol. 5, 295–308 (1928)
Hopkins, C.R.: The biosynthesis, intracellular transport, and packaging of melanocyte-stimulating peptides in the amphibian pars intermedia. J. Cell Biol. 53, 642–653 (1972)
Howe, A., Maxwell, D.S.: Electron microscopy of the pars intermedia of the pituitary gland in the rat. Gen. Comp. Endocrinol. 11, 169–185 (1968)
Imai, K.: 6. Light and electron microscopic studies on the pars intermedia of the pituitary of Xenopus laevis under different experimental conditions. Gunma Symp. Endocrinol. 6, 89–105 (1969)
Kleinholz, L.H.: Studies in reptilian colour changes II. The pituitary and adrenal glands in the regulation of the melanophores of Anolis carolinensis. J. Exp. Biol. 15, 474–491 (1938a)
Kleinholz, L.H.: Studies in reptilian colour changes III. Control of the light phase and behaviour of isolated skin. J. Exp. Biol. 15, 492–499 (1938b)
Larsson, L., Rodríguez, E.M., Meurling, P.: Control of the pars intermedia of the lizard, Anolis carolinensis. III. Changes in the ultrastructure of the disconnected neuro-intermediate lobe. Cell Tissue Res. 199, in press (1979)
Meurling, P., Fremberg, M.: Effects of partial denervations of the neuro-intermediate lobe in the skate, Raja radiata. Acta Zool. 55, 7–15 (1974)
Meurling, P., Klefbohm, B.: Control of pars intermedia activity in late embryos of the spiny dogfish, Squalus acanthias. Cell Tissue Res. 155, 221–229 (1974)
Meurling, P., Willstedt, A.: Vascular connections in the pituitary of Anolis carolinensis with special reference to the pars intermedia. Acta Zool. 51, 211–218 (1970)
Meyer, J., Brooks, G.R.: Effect of blinding and parietalectomy on color change in Anolis carolinensis (Reptilia: Iguanidae). Virginia J. Sci. 19, 122–125 (1968)
Nayar, S., Pandalai, K.R.: Pars intermedia of the pituitary gland and integumentary colour changes in the garden lizard Calotes versicolor. Z. Zellforsch. 58, 837–845 (1963)
Pearson, A.K., Licht, P.: Embryology and cytodifferentiation of the pituitary gland in the lizard Anolis carolinensis. J. Morphol. 144, 85–118 (1974)
Perryman, E.K.: Fine structure of the secretory activity of the pars intermedia of Rana pipiens. Gen. Comp. Endocrinol. 23, 94–110 (1974)
Perryman, E.K.: Permeability of the amphibian pars intermedia to peroxidase injected intravascularly. Cell Tissue Res. 173, 401–406 (1976)
Rahn, H., Rosendale, F.: Diurnal rhythm of melanophore hormone secretion in the Anolis pituitary. Proc. Soc. Exp. Biol. Med. 48, 100–102 (1941)
Rodríguez, E.M., La Pointe, J.: Histology and ultrastructure of the neural lobe of the lizard, Klauberina riversiana. Z. Zellforsch. 95, 37–57 (1969)
Rodríguez, E.M., La Pointe, J.: Light and electron microscopic study of the pars intermedia of the lizard, Klauberina riversiana. Z. Zellforsch. 104, 1–13 (1970)
Rodríguez, E.M., Gimenez, A.: Comparative aspects of nervous control of pars intermedia. Gen. Comp. Endocrinol. 3, 97–107 (1972)
Rodríguez, E.M., Larsson, L., Meurling, P.: Control of the pars intermedia of the lizard, Anolis carolinensis. I. Ultrastructure of the intact neural lobe. Cell Tissue Res. 186, 241–258 (1978)
Terlou, M., Goos, H.J.Th., van Oordt, P.G.W.J.: Hypothalamic regulation of pars intermedia activity in amphibians, Fortschr. Zool. 22, 117–133 (1974)
Törk, I.: Light and electron microscopic studies on the pars intermedia of the chameleon. Cell Tissue Res. 168, 223–238 (1976)
Volcanes, B. De, Weatherhead, B.: Early changes in the ultrastructure of the pars intermedia of the pituitary of Xenopus laevis after change of background color. Neuroendocrinology 22, 127–133 (1976)
Weatherhead, B.: Cytology of the neuro-intermediate lobe of the tuatara, Sphenodon punctatus Gray. Z. Zellforsch. 119, 21–42 (1971)
Weatherhead, B.: Comparative cytology of the neuro-intermediate lobe of the reptilian pituitary. Zentralbl. Veterinärmed. C. Anatomie, Histologie, Embryologie 7, 84–119 (1978)
Weatherhead, B., Whur., P.: Quantification of ultrastructural changes in the “melanocyte-stimulating hormone cell” of the pars intermedia of the pituitary of Xenopus laevis, produced by change of background colour. J. Endocrinol. 53, 313–310 (1972)
Zoond, A., Eyre, J.: II. Studies in reptilian colour response. I. — The bionomics and physiology of the pigmentary activity of the chameleon. Philos. Trans. B. 223, 27–55 (1934)