Skip to main content
SpringerLink
Log in

The hypophyseal pars tuberalis is enriched with distinct phosphotyrosine-containing proteins not detected in other areas of the brain and pituitary

  • Published:
Cell and Tissue Research Aims and scope Submit manuscript

Abstract

The regulation of cell activity, growth and metabolism by a number of growth factor receptors and proto-oncogene products involves tyrosine kinase activity resulting in autophosphorylation of the receptors and production of phosphorylated tyrosine-containing protein substrates. The identification and precise localization of phosphotyrosine (PY)-containing proteins are first steps in elucidating the functional role of tyrosine kinases in the modulation of the central nervous system and related areas. In the present report, we describe PY-containing proteins in the median eminence and adjacent pars tuberalis of the rat adenohypophysis by immunocytochemistry using light and electron microscopy, and by Western blotting analysis. PY-immunoreactivity was found to be most intense throughout the cytoplasm of a population of epithelial pars tuberalis cells. Polyacrylamide gel electrophoresis and Western blotting of tissue extracts from various brain and pituitary regions demonstrated a general pattern of 4 major bands of PY-proteins, with an additional dense band representing a 44 kDa protein that was highly phosphorylated on tyrosines and that was exclusively found in the pars tuberalis. Additional investigation for the presence of insulin receptors, a tyrosine kinase previously correlated with the distribution of PY-proteins, demonstrated a receptor localization in axons and nerve terminals in the external and internal zone of the median eminence. However, the large amount of different PY-proteins present in the secretory cell population of the pars tuberalis could not be attributed to the insulin receptor. Our findings demonstrate that there is a large amount of cell-specific tyrosine kinase activity in the median eminence and contacting the pars tuberalis; these may play a significant role for transduction of biological signals or metabolic regulation in the neuroendocrine region.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Aguado F, Martinez-Murillo R, Sanchez-Franco F, Mellström B (1992) Distribution of insulin-like growth factor I receptor mRNA in rat brain. Relevance in the hypothalamo-hypophyseal system (abstract) Eur J Neurosci [Suppl 5]:306

  • Baker BL, Yu YY (1975) Immunocytochemical analysis of cells in the pars tuberalis of the rat hypophysis with antisera to hormones in the pars distalis. Cell Tissue Res 156:443–449

    Google Scholar 

  • 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

    Google Scholar 

  • Baskin DG, Figlewicz DP, Woods SC, Porte D Jr, Dorsa DM (1987) Insulin in the brain. Annu Rev Physiol 49:335–347

    Google Scholar 

  • Baskin DG, Wilcox BJ, Figlewicz DP, Dorsa DM (1988) Insulin and insulin-like growth factors in the CNS. Trends Neurosci 11:107–111

    Google Scholar 

  • Baumert M, Takei K, Hartinger J, Burger PM, Mollard GF von, Maycox PR, De Camilli P, Jahn R (1990) p29: A novel tyrosine-phosphorylated membrane protein present in small clear vesicles of neurons and endocrine cells. J Cell Biol 110:1285–1294

    Google Scholar 

  • Bergmann M, Wittkowski W, Hoffmann K (1989) Ultrastructural localization of thyrotropin (TSH)-like immunoreactivity in specific secretory cells of the hypophyseal pars tuberalis in the Djungarian hamster, Phodopus sungorus. Cell Tissue Res 256:649–652

    Google Scholar 

  • Bohannon NJ, Figlewicz DP, Corp ES, Wilcox BJ, Porte D Jr, Baskin DG (1986) Identification of binding sites for an insulin-like growth factor (IGF-1) in the median eminence of the rat brain by quantitative autoradiography. Endocrinology 119:943–945

    Google Scholar 

  • Bohannon NJ, Corp ES, Wilcox BJ, Figlewicz DP, Dorsa DM, Baskin DG (1988) Localization of binding sites for insulin-like growth factor-I (IGF-I) in the rat brain by quantitative autoradiography. Brain Res 444:205–213

    Google Scholar 

  • Corp ES, Woods SC, Porte D Jr, Dorsa DM, Figlewicz DP, Baskin DG (1986) Localization of 125I-Insulin binding sites in the rat hypothalamus by quantitative autoradiography. Neurosci Lett 70:17–22

    Google Scholar 

  • Dellmann HD, Stoeckel ME, Hindelang-Gertner C, Porte A, Stutinsky F (1974) A comparative ultrastructural study of the pars tuberalis of various mammals, the chicken and the newt. Cell Tissue Res 148:313–329

    Google Scholar 

  • Ellis PD, Bissoon N, Gurd JW (1988) Synaptic protein tyrosine kinase: partial characterization and identification of endogenous substrates. J Neurochem 51:611–620

    Google Scholar 

  • 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

    Google Scholar 

  • Hanley MR (1988) Proto-oncogenes in the nervous system. Neuron 1:175–182

    Google Scholar 

  • Kahn CR, White MF (1988) The insulin receptor and the molecular mechanism of insulin action. J Clin Invest 82:1151–1156

    Google Scholar 

  • Kamps MP (1991) Generation and use of anti-phosphotyrosine antibodies for immunoblotting. Methods Enzymol 201:101–110

    Google Scholar 

  • Kobayashi T, Kobayashi T, Yamamoto K, Inatomi M (1963) Electron microscopy observation on the hypothalamo-hypophyseal system in the rat. I. The ultrafine structure of the contact region between the external layer of the infundibulum and pars tuberalis of the anterior pituitary. Endocrinol Jpn 10:69–80

    Google Scholar 

  • Laemmli UK (1970) Cleavage of structural proteins during assembly of the head of bacteriophage T. Nature 227:680–685

    Google Scholar 

  • Lesniak MA, Hill MA, Kiess W, Rojeski M, Pert CB, Roth J (1988) Receptors for insulin-like growth factors I and II: autoradiographic localization in rat brain and comparison to receptors for insulin. Endocrinology 123:2089–2099

    Google Scholar 

  • Luschka H (1860) Der Hirnanhang und die Steißdrüse des Menschen. Springer, Berlin

    Google Scholar 

  • Marks JL, Porte D Jr, Baskin DG (1991) Localization of type I insulin-like growth factor receptor messenger RNA in the adult rat brain by in situ hybridization. Mol Endocrinol 5:1158–1168

    Google Scholar 

  • Merchenthaler I (1991) Current status of brain hypophysiotropic factors-morphological aspects. TEM 2:219–226

    Google Scholar 

  • Mitchison T, Kirschner M (1988) Cytoskeletal dynamics and nerve growth. Neuron 1:761–772

    Google Scholar 

  • Morgan PJ, Williams LM, Davidson G, Lawson W, Howell E (1989) Melatonin receptors on ovine pars tuberalis: characterization and autoradiographical localization. J Neuroendocrinol 1:1–4

    Google Scholar 

  • Moss AM, Unger JW, Moxley RT, Livingston JN (1990) Location of phosphotyrosine-containing proteins by immunocytochemistry in the rat forebrain corresponds to the distribution of the insulin receptor. Proc Natl Acad Sci USA 87:4453–4457

    Google Scholar 

  • Nitsch C, Riesenberg R (1988) Immunocytochemical demonstration of GABAergic synaptic connections in rat substantia nigra after different lesions of the strionigral projection. Brain Res 461:127–142

    Google Scholar 

  • Ordronneau P, Petrusz P (1980) Immunocytochemical demonstration of anterior pituitary hormones in the pars tuberalis of long-term hypophysectomized rats. Am J Anat 158:491–506

    Google Scholar 

  • Pyper JM, Bolen JB (1990) Identification of a novel neuronal c-src exon expressed in human brain. Mol Cell Biol 10:2035–2040

    Google Scholar 

  • Rosen OM (1989) Structure and function of insulin receptors. Diabetes 38:1508–1511

    Google Scholar 

  • Schulze-Bonhage A, Wittkowski W (1990) Age-dependent changes of ultrastructure and thyroid-stimulating hormone immunore-activity in the pars tuberalis of the rat. Acta Anat 139:134–140

    Google Scholar 

  • Sternberger LA (1979) Immunocytochemistry, 2nd edn. Wiley, New York

    Google Scholar 

  • Sugrue MM, Bruge JS, Marshak DR, Greengard P, Gustafson EL (1990) Immunocytochemical localization of the neuron-specific form of the c-src gene product, pp60c-src(+), in rat brain. J Neurosci 10:2513–2527

    Google Scholar 

  • Tilney F (1913) An analysis of the juxtaneural epithelial portion of the hypophysis cerebri with an embryological and histological account of an hitherto undescribed part of the organ. Anat Physiol 30:258–293

    Google Scholar 

  • Ullrich A, Schlessinger J (1990) Signal transduction by receptors with tyrosine kinase activity. Cell 61:203–212

    Google Scholar 

  • Unger J, McNeill TH, Moxley III RT, White M, Moss A, Livingston JN (1989) Distribution of insulin receptor-like immunoreactivity in the rat forebrain. Neuroscience 31:143–157

    Google Scholar 

  • Unger JW, Moss AM, Livingston JN (1991a) Immunohistochemical localization of insulin receptors and phosphotyrosine in the brainstem of the adult rat. Neuroscience 42:853–861

    Google Scholar 

  • Unger JW, Livingston JN, Moss AM (1991b) Insulin receptors in the central nervous system: localization, signalling mechanisms and functional aspects. Prog Neurobiol 36:343–362

    Google Scholar 

  • Van Houten M, Posner BI (1981) Insulin receptors in the central nervous system: localization and characterization. In: Andreani D, De Pirro R, Lauro R, Olefsky J, Roth J (eds) Current views on insulin receptors, vol 41. Serono Symposia. Academic Press, London New York, pp 75–90

    Google Scholar 

  • Van Houten M, Posner BI, Kopriwa BM, Brawer JR (1989) Insulin binding sites localized to nerve terminals in rat median eminence and arcuate nucleus. Science 207:1081–1083

    Google Scholar 

  • Wagner KR, Mei L, Huganir RL (1991) Protein tyrosine kinases and phosphatases in the nervous system. Curr Opin Neurobiol 1:65–74

    Google Scholar 

  • Warren SL, Nelson J (1987) Nonmitogenic morphoregulatory action of pp60v-src on multicellular epithelial structures. Mol Cell Biol 7:1326–1337

    Google Scholar 

  • Watson RE Jr, Wiegand SJ, Clough RW, Hoffman GE (1986) Use of cryoprotectant to maintain long-term peptide immunoreactivity and tissue morphology. Peptides 7:155–159

    Google Scholar 

  • White MR, Backer JM (1991) Preparation and use of anti-phosphotyrosine antibodies to study structure and function of insulin receptors. Methods Enzymol 201:65–79

    Google Scholar 

  • Wiestler OD, Walter G (1988) Developmental expression of two forms of pp60c-src in mouse brain. Mol Cell Biol 8:502–504

    Google Scholar 

  • Williams LM, Morgan PJ (1988) Demonstration of melatonin binding sites in the pars tuberalis of the rat. J Endocrinol 119:R1–3

    Google Scholar 

  • Wittkowski WH, Schulze-Bonhage AH, Böckers TM (1992) The pars tuberalis of the hypophysis: a modulator of the pars distalis? Acta Endocrinol 126:285–290

    Google Scholar 

  • Yarden Y, Ullrich A (1988) Growth factor receptor tyrosine kinases. Annu Rev Biochem 57:443–478

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Anatomische Anstalt der Universität München, Pettenkoferstrasse 11, W-8000, München 2, Germany

    J. W. Unger

  2. Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, 14642, Rochester, NY, USA

    A. M. Moss

  3. Department of Medicine (Endocrine Metabolism Unit), University of Rochester Medical Center, 601 Elmwood Avenue, 14642, Rochester, NY, USA

    J. N. Livingston

Authors
  1. J. W. Unger
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. A. M. Moss
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. J. N. Livingston
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

This paper is dedicated to Professor Dr. Leonhardt on the occasion of his 75th birthday

Rights and permissions

Reprints and permissions

About this article

Cite this article

Unger, J.W., Moss, A.M. & Livingston, J.N. The hypophyseal pars tuberalis is enriched with distinct phosphotyrosine-containing proteins not detected in other areas of the brain and pituitary. Cell Tissue Res 272, 499–507 (1993). https://doi.org/10.1007/BF00318556

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00318556

Key words

Search

Navigation