Summary
Luteinizing hormone-releasing hormone (LH-RH) was localized in neurons of the arcuate nucleus and median eminence, and in many of the nerve fibres of the median eminence of the rat, by using antisera to synthetic LH-RH with the immunoglobulin-peroxidase technique or by using a soluble peroxidase-antiperoxidase complex at the electron microscopic level. Many of the arcuate neurons and some of the median eminence neurons contained numerous densely stained granules (diameter about 90–130 nm) associated with the Golgi complex, and scattered granules elsewhere in the cytoplasm. Similar granules, positive for LH-RH, were observed in many nerve profiles around the capillaries of the primary portal plexus of zona palisadica and zona granulosa of the median eminence, and such profiles may represent the release sites of LH-RH into the portal vessels. About 20% of the nerve profiles around the primary portal plexus were LH-RH positive and the rest of the nerve profiles were negative. The negative profiles may belong to other hypophysiotropic hormones and/or to catecholaminergic fibers. Some nerve endings at the ventricular surface of the ependymal cells, in contact with the ventricular fluid, were also LH-RH positive. These nerve endings probably release their secretion into the cerebrospinal fluid.
There was no staining of the mitochondria, the nuclei or the axonal membranes. Stain of varying intensity was seen in the secretory granules, and within and around the cisternae of the Golgi complex. The stained granules in the cisternae were pleomorphic. From these observations it was concluded that the LH-RH is packaged or condensed into granules in the Golgi cisternae.
Similar content being viewed by others
References
Akmayev, I. G., Réthelyi, M., Majorossy, K.: Changes induced by adrenalectomy in nerve endings of the hypothalamic median eminence (zona palisadica) in the albino rat. Acta biol. Acad. Sci. hung. 18, 187–200 (1967)
Barry, J., Dubois, M. P., Poulain, P.: LRP producing cells of the mammalian hypothalamus. A fluorescent antibody study. Z. Zellforsch. 146, 351–366 (1973)
Brawer, J. R.: The role of the arcuate nucleus in the brain pituitary-gonad axis. J. comp. Neurol. 143, 411–446 (1971)
Clementi, F., Ceccarelli, B.: Fine structure of rat hypothalamic nuclei. In: The hypothalamus (eds. L. Martini, M. Motta, F. Fraschini), p. 17–44. New York-London: Academic Press 1970
Flament-Durand, Desclin, L.: The hypophysiotropic area. In: The hypothalamus (eds. L. Martini, M. Motta, F. Fraschini), p. 245–256. New York-London: Academic Press 1970
Fuxe, K., Hökfelt, T.: The influence of central catecholamine neurons on the hormone secretion from the anterior and posterior pituitary. In: Neurosecretion (ed. F. Stutinsky), p. 165–177. Berlin-Heidelberg-New York: Springer 1967
Fuxe, K., Hökfelt, T.: Catecholamines in the hypothalamus and the pituitary gland. In: Frontiers in neuroendocrinology (eds. W. F. Ganong, L. Martini), p. 47–97. New York-London-Toronto: Oxford University Press 1969
Ishii, S.: Isolation and identification of secretory vesicles in the axons of the equine median eminence. Gunma Symp. Endocr. 7, 1–11 (1970)
Ishii, S.: Classification and identification of neurosecretory granules in the median eminence. In: Brain-endocrine interaction. Median eminence: Structure and function (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 119–141. Basel: Karger 1972
Ishii, S., Iwata, T., Kobayashi, H.: Granular localization of corticotropin-releasing activity in horse hypophysial stalk homogenate. Endocr. jap. 16, 171–177 (1969)
Kendall, J. W., Jacobs, J. J., Kramer, R. M.: Studies on the transport of hormones from the cerebrospinal fluid to hypothalamus and pituitary. In: Brain-endocrine interaction. Median eminence: Structure and function (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 342–349. Basel: Karger 1972
King, J. C.: Ultrastructural analysis of arcuate neurons in normal and androgenized female rats. Ph. D. thesis submitted to Tulane University, p. 1–148 (1972), University Microfilms, A Xerox Company, Ann Arbor, Michigan, U.S.A.
Knigge, K. M., Silverman, A. J.: Transport capacity of the median eminence. In: Brainendocrine interaction. Median eminence: Structure and function (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 350–363. Basel: Karger 1972
Kobayashi, H., Matsui, T.: Pine structure of the median eminence and its functional significance. In: Frontiers in neuroendocrinology (eds. W. F. Ganong, L. Martini), p. 3–46. New York-London-Toronto: Oxford University Press 1969
Kobayashi, H., Matsui, T., Ishii, S.: Functional electron microscopy of the hypothalamic median eminence. Int. Rev. Cytol. 29, 281–381 (1970)
Moriarty, G. C., Halmi, N. S.: Adrenocorticotropin production by the intermediate lobe of the rat pituitary: an electron microscopic-immunohistochemical study. Z. Zellforsch. 132, 1–14 (1972)
Mulder, A. H.: On the subcellular localization of corticotropin-releasing factor (CRF) in the rat median eminence. Progr. Brain Res. 32, 33–41 (1970)
Naik, D. V.: Immunohistochemical localization of adrenocorticotropin and melanocyte stimulating hormone in pars intermedia of rat hypophysis. Z. Zellforsch. 142, 289–304 (1973a)
Naik, D. V.: Electron microscopic-immunocytochemical localization of adrenocorticotropin and melanocyte stimulating hormone in the pars intermedia cells of the rats and mice. Z. Zellforsch. 142, 305–328 (1973b)
Naik, D. V.: Immunohistochemical and immunofluorescent localization of LH-RF neurons in the hypothalamus of rat. Anat. Rec. 178, 424 (1974a)
Naik, D. V.: Immunohistochemical localization of luteinizing hormone-releasing hormone in the mammalian hypothalamus. In: Symposium on Neuroendocrine regulation of fertility. Simla (ed. T. C. Anand Kumar). Basel: Karger 1974b (in press)
Naik, D. V.: Immunoreactive LH-RH neurons in the hypothalamus identified by light and fluorescent microscopy. Cell Tiss. Res. 157, 423–436 (1975)
Nakane, P. K.: Application of peroxidase-labelled antibodies to the intracellular localization of hormones. Acta endocr. (Kbh.), Suppl. 153, 190–204 (1971)
Rinne, U. K.: Effect of adrenalectomy on the ultrastructure and catecholamine fluorescence of the nerve endings in the median eminence of the rat. In: Brain-endocrine interaction. Median eminence: Structure and function (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 164–170. Basel: Karger 1972
Rodríguez, E. M.: Morphological and functional relationships between the hypothalamo-neurohypophysial system and cerebrospinal fluid. In: Aspects of neuroendocrinology (eds. W. Bargmann, B. Scharrer), p. 352–365. Berlin-Heidelberg-New York: Springer 1970
Rodríguez, E. M.: Comparative and functional morphology of the median eminence. In: Brain-endocrine interaction. Median eminence: Structure and function (eds. K. M. Knigge, D. E. Scott, A. Weindl), p. 319–334. Basel: Karger 1972
Scott, D. E., Knigge, K. M.: Ultrastructural changes in the median eminence of the rat following deafferentation of the basal hypothalamus. Z. Zellforsch. 105, 1–32 (1970)
Sterba, G., Brücker, G.: Zur Funktion der ependymalen Glia in der Neurohypophyse. Z. Zell-forsch. 81, 457–473 (1967)
Stoeckart, R., Kreike, A. J., Jansen, H. G.: Sizes of granular vesicles in the rat median eminence, with special reference to the zona granulosa. Z. Zellforsch. 146, 501–515 (1973)
Szentágothai, J., Flerkó, B., Mess, B., Halász, B.: Anatomical considerations. In: Hypothalamic control of the anterior pituitary, p. 22–109. Budapest: Akademiai Kiadó 1968
Wittkowski, W.: Zur funktionellen Morphologie ependymaler und extraependymaler Glia im Rahmen der Neurosekretion. Z. Zellforsch. 86, 111–128 (1968)
Zambrano, D., Robertis, E.: The effect of castration upon the ultrastructure of the rat hypothalamus. II. Arcuate nucleus and outer zone of the median eminence. Z. Zellforsch. 87, 409–421 (1968)
Author information
Authors and Affiliations
Additional information
This study was supported by MRC Canada Grant no. MA-5160.
The author wishes to thank Drs. Morry Givner and Michael Hirsch of Ayerst Research Laboratories, Montreal, for providing the synthetic LH-RH decapeptide (AY-24, 031) and its antiserum, and Mr. Gaston Lambert for his excellent photography.
Rights and permissions
About this article
Cite this article
Naik, D.V. Immuno-electron microscopic localization of luteinizing hormone-releasing hormone in the arcuate nuclei and median eminence of the rat. Cell Tissue Res. 157, 437–455 (1975). https://doi.org/10.1007/BF00222598
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00222598