Summary
Forty autopsy pituitaries were studied to elucidate the histology, immunocytology and ultrastructure of pars tuberalis in subjects with normal and abnormal endocrine homeostasis. Pars tuberalis consisted mainly of gonadotrophs interspersed with few corticotrophs and thyrotrophs, histologically resembling those of pars distalis. Somatotrophs and lactotrophs were not identified. There were no histologic differences attributable to age or sex. In cases of glucocorticoid excess, pars tuberalis corticotrophs showed Crooke's hyalinization. Following castration or hypophysectomy, pars tuberalis gonadotrophs exhibited more intense immunostaining for FSH1 and LH than did normals. Ultrastructural analysis revealed gonadotrophs and corticotrophs showing no evidence of active secretion; immunoelectron microscopy demonstrated FSH, LH and ACTH in secretory granules. By light microscopy, squamous nests, often identified in pars tuberalis, were positive for immunoreactive keratin; cells at their periphery contained FSH, LH or ACTH, indicating derivation of nests by squamous metaplasia from gonadotrophs and corticotrophs. By electron microscopy, clusters of epithelial cells containing desmosomes and tonofilaments were surrounded by granulated gonadotrophs.
Human pars tuberalis cells represent mainly a subpopulation of gonadotrophs possessing all organelles required for synthesis and storage of hormones but showing ultrastructural features of functional inactivity; the reasons for this inactivity and for the formation of squamous nests remain unexplained.
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References
Asa SL, Kovacs K, Bilbao JMB, Penz (1981) Immunohistochemical localization of keratin in craniopharyngiomas and squamous cell nests of the human pituitary. Acta Neuropathol (Berl) 54:257–260
Baker BL (1977) Cellular composition of the human pituitary pars tuberalis as revealed by immunocytochemistry. Cell Tissue Res 182:151–163
Baker BL, Yu YY (1975) Immunocytochemical analysis of cells in the pars tuberalis of the rat hypophysis with antisera to hormones of the pars distalis. Cell Tissue Res 156:443–449
Baker BL, Karsch FJ, Hoffman DL, Beckman WC Jr (1977) The presence of gonadotropic and thyrotropic cells in the pituitary pars tuberalis of the monkey (Macaca mulatta). Biol Reprod 17:232–240
Biggart JH (1949) Pathology of the nervous system: A student's introduction. Ed 2. Williams & Wilkins Co, Baltimore
Bloodworth JMB Jr, Horvath E, Kovacs K (1980) Fine structural pathology of the endocrine system. In: Trump F, Jones RT (eds) Diagnostic electron microscopy, vol 3, J. Wiley & Sons Inc, New York
Carmichael HT (1931) Squamous epithelial rests in the hypophysis cerebri. Arch Neurol Psych 26:966–975
Cheetham HD (1963) Experimental squamous metaplasia and squamous epithelioma formation in the pituitary of the rat. Brit J Cancer 17:657–662
Conway LW, Collins WF (1969) Results of transphenoidal cryohypophysectomy for carcinoma of the breast. N Engl J Med 281:1–7
DeLellis RA (1981) Basic techniques of immunohistochemistry. In: DeLellis RA (ed) Diagnostic immunohistochemistry. Masson Pub USA Inc.
Erdheim J (1904) Über Hypophysenganggeschwülste und Hirncholesteatome. SB Akad Wiss, Wein 113:537–726
Girod C, Dubois MP, Trouillas J (1980) Immunohistochemical study of the pars tuberalis of the adenohypophysis in the monkey, Macaca irus. Cell Tissue Res 210:191–203
Goldberg GH, Eshbaugh DE (1960) Squamous cell nests of the pituitary gland as related to the origin of craniopharyngiomas. Arch Pathol 70:293–299
Gross DS (1978) Effect of castration and steroid replacement on immunoreactive luteinizing hormone cells in the pars tuberalis of the rat. Endocrinology 103:583–588
Gross DS, Page RB (1979) Luteinizing hormone and follicle-stimulating hormone production in the pars tuberalis of hypophysectomized rats. Am J Anat 156:285–291
Heller H, Hassan S, Saifi AQ (1968) Antidiuretic activity in the cerebrospinal fluid. J Endocrinol 41:273–280
Hunter IJ (1955) Squamous metaplasia of cells of the anterior pituitary gland. J Pathol Bacteriol 69:141–145
Kiyono H (1924) Über das Vorkommen von Plattenepithelherden in der Hypophyse. Virchows Arch [Pathol Anat] 252:118–145
Knowles F (1972) Ependyma of the third ventricle in relation to pituitary function. Prog Brain Res 38:255–270
Knowles F, Anand Kumar TC (1969) Structural changes related to reproduction in the hypothalamus and in the pars tuberalis of the rhesus monkey. Part II. The Pars Tuberalis. Philos Trans R Soc London [Biol] 256:375–395
Kovacs K, Horvath E, Ryan N (1981) Immunocytology of the human pituitary. In: De Lellis RA (ed) Diagnostic immunohistochemistry. Masson Pub USA Inc
Lachelin GD, Yen SSC, Alksne JF (1977) Hormonal changes following hypophysectomy in humans. Obstet Gynecol 50:333–338
LeBeau J, Nicolaidis S, Foncin JF (1963) Étude anatomique et biologique de seize cas de mischotomie pour cancers hormonodépendants. Actualités endocrinologiques 4e série, Expansion Scient Paris 227–235
Legait H (1969) Recherches expérimentales sur le lobe tuberal de l'hypophyse chez le rat impubère. CR Soc Biol (Paris) 163:714–715
Luschka H (1860) Der Hirnanhang und die Steissdrüse des Menschen. Springer, Berlin Heidelberg New York
Luse SA, Kernohan JW (1955) Squamous-cell nests of the pituitary gland. Cancer 8:623–628
Midgley AR Jr (1966) Human pituitary luteinizing hormone: an immunohistochemical study. J Histochem Cytochem 14:159–166
Moriarty GC, Moriarty CM, Sternberger LA (1973) Ultrastructural immunocytochemistry with unlabeled antibodies and the peroxidase-antiperoxidase complex. A technique more sensitive than radioimmunoassay. J Histochem Cytochem 21:825–833
Ordronneau P, Petrusz P (1980) Immunocytochemical demonstration of anterior pituitary hormones in the pars tuberalis of long-term hypophysectomized rats. Am J Ant 158:491–506
Osamura RY, Watanabe K (1978) An immunohistochemical study of epithelial cells in the posterior lobe and pars tuberalis of the human adult pituitary gland. Cell Tissue Res 194:513–524
Reichlin S (1963) Neuroendocrinology. N Engl J Med 269:1182–1191
Romeis B (1940) Innersekretorische Drüsen. Hypophyse. In: Möllendorff W von (ed) Handbuch der mikroskopischen Anatomie des Menschen. VI/3 Springer, Berlin Heidelberg New York
Schlegel R, Banks-Schlegel S, Pinkus GS (1980) Immunohistochemical localization of keratin in normal human tissues. Lab Invest 42:91–96
Susman W (1931–32) Embryonic epithelial rests in the pituitary. Br J Surg 19:571–576
Uemura H, Asai T, Nozaki N, Kobayashi H (1975) Ependymal absorption of luteinizing hormone-releasing hormone injected into the third ventricle of the rat. Cell Tissue Res 160:443–452
Uemura H, Kobayashi H (1977) Effects of gonadal function by lesioning tanycytes in the median eminence of the rat and Japanese quail. Cell Tissue Res 178:143–153
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Asa, S.L., Kovacs, K. & Bilbao, J.M. The pars tuberalis of the human pituitary. Vichows Archiv A Pathol Anat 399, 49–59 (1982). https://doi.org/10.1007/BF00666218
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DOI: https://doi.org/10.1007/BF00666218