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Ultrastructure of the pars intermedia of the adult sheep hypophysis

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Light microscopy of coronal sections of the sheep pars intermedia revealed a compact, incompletely lobulated V-shaped region about 15–20 cells thick, situated between the pars distalis and the pars nervosa. A prominent hypophysial cleft and follicles containing a colloid-like substance were seen.

Using electron microscopy, five cell types could be distinguished: pars intermedia glandular cells, pars distalis-like glandular cells, interstitial cells, follicular cells and cleft lining cells. The polyhedral to pear-shaped pars intermedia glandular cells predominated. They contained dense-cored, membrane-bound granules near the Golgi complex, and larger, irregular vesicles with finely granular contents of varying electron density throughout the remaining cytoplasm; exocytotic release of granules was occasionally observed. Smaller numbers of cells resembling those seen in the pars distalis were scattered throughout the pars intermedia. Interstitial cells usually possessed elongated cytoplasmic processes which extended between the glandular cells, and were characterized by deeply indented nuclei, elaborate junctional complexes and an absence of cytoplasmic granules. Cells lining the follicles resembled the interstitial cells. The major cells bordering the hypophysial cleft were triangular in section and bore irregular microvilli on their free surface. The pars intermedia appeared to be less vascular than the remainder of the hypophysis and only occasional fenestrated capillaries were seen. Nerve profiles were rare.

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  1. Anand Kumar TC, Vincent DS (1974) Fine structure of the pars intermedia in the rhesus monkey, Macaca mulatta. J Anat 118:155–169

  2. Bargmann W, Lindner E, Andres KH (1967) Über Synapsen an endokrinen Epithelzellen und die Definition sekretorischer Neurone. Untersuchungen am Zwischenlappen der Katzenhypophyse. Z Zellforsch 77:282–298

  3. Basset JR, Pollard I (1980) The involvement of coated vesicles in the secretion of corticosterone by the zona fasciculata of the rat adrenal cortex. Tissue Cell 12:101–115

  4. Bergland RM, Torack RM (1969) An ultrastructural study of follicular cells in the human anterior pituitary. Am J Pathol 57:273–297

  5. Birk Y, Li CH (1964) Isolation and properties of a new biologically active peptide from sheep pituitary glands. J Biol Chem 239:1048–1052

  6. Bloom F, Battenberg E, Rossier J, Ling N, Lepaluoto J, Vargo TM, Guillemin R (1977) Endorphins are located in the intermediate and anterior lobes of the pituitary gland, not in the neurohypophysis. Life Sci 20:43–48

  7. Cameron E, Foster CL (1971) Some light and electron-microscopical observations on the pars intermedia of the pituitary gland of the rabbit. J Endocrinol 49:479–485

  8. Chatterjee P (1975) Development and cytodifferentiation of the rabbit pars intermedia. I. Fetal and perinatal stages. Cell Tissue Res 164:481–501

  9. Chatterjee P (1976) Development and cytodifferentiation of the rabbit pars intermedia. II. Neonatal to adult. J Anat 122:415–433

  10. Crine P, Benjannet S, Seidah NG, Lis M, Chrétien M (1977) In vitro biosynthesis of β-endorphin, γ lipotropin, and β-lipotropin by the pars intermedia of beef pituitary glands. Proc Natl Acad Sci USA 74:4276–4280

  11. Crine P, Gianoulakis C, Seidah NG, Gossard F, Pezalla PD, Lis M, Chrétien M (1978) Biosynthesis of β endorphin from β-lipotropin and a larger molecular weight precursor in rat pars intermedia. Proc Natl Acad Sci USA 75:4719–4723

  12. Daniel PM, Prichard MML (1957) The vascular arrangements of the pituitary gland of the sheep. Q J Exp Physiol 42:237–248

  13. Farquhar MG (1957) “Corticotrophs” of the rat adenohypophysis as revealed by electron microscopy. Anat Rec 127:291

  14. Farquhar MG (1961) Fine structure and function in capillaries of the anterior pituitary gland. Angiology 12:270–292

  15. Farquhar MG (1971) Processing of secretory products by cells of the anterior pituitary gland. In: Heller H, Lederis K (eds) Memoirs of the society for endocrinology. Cambridge University Press, No 19, pp 79–122

  16. Farquhar MG (1978) Recovery of surface membrane in anterior pituitary cells. Variations in traffic detected with anionic and cationic ferritin. J Cell Biol 77:R35–42

  17. Green JD (1951) The comparative anatomy of the hypophysis, with special reference to its blood supply and innervation. Am J Anat 88:225–311

  18. Howe A (1973) The mammalian pars intermedia: a review of its structure and function. J Endocrinol 59:385–409

  19. Howe A, Maxwell DS (1968) Electron microscopy of the pars intermedia of the pituitary gland in the rat. Gen Comp Endocrinol 11:169–185

  20. Kagayama M (1965) The follicular cell in the pars distalis of the dog pituitary gland: an electron microscope study. Endocrinology 77:1053–1060

  21. Kobayashi S, Sasagawa T (1976) Morphological aspects of the secretion of gastro-enteric hormones. In: Fujita T (ed) Endocrine gut and pancreas. Elsevier Scientific Publishing Company, Amsterdam, pp 255–271

  22. Kurosumi K, Matsuzawa T, Shibasaki S (1961) Electron microscope studies on the fine structures of the pars nervosa and pars intermedia, and their morphological interrelation in the normal rat hypophysis. Gen Comp Endocrinol 1:433–452

  23. Mains RE, Eipper BA, Ling N (1977) Common precursor to corticotropins and endorphins. Proc Natl Acad Sci USA 74:3014–3018

  24. Nakanishi S, Inoue A, Kita T, Numa S, Chang ACY, Cohen SN, Nunberg J, Schimke RT (1978) Construction of bacterial plasmids that contain the nucleotide sequence for bovine corticotropin-β-lipotropin precursor. Proc Natl Acad Sci USA 75:6021–6025

  25. Silman RE, Holland D, Chard T, Lowry PJ, Hope J, Rees LH, Thomas A, Nathanielsz P (1979) Adrenocorticotrophin-related peptides in adult and foetal sheep pituitary glands. J Endocrinol 81:19–34

  26. Siperstein ER, Allison VF (1965) Fine structure of cells responsible for secretion of adrenocorticotropin in the adrenalectomized rat. Endocrinology 76:70–79

  27. Stoeckel ME, Dellmann HD, Porte A, Klein MJ, Stutinsky F (1973) Corticotrophic cells in the rostral zone of the pars intermedia and in the adjacent neurohypophysis of the rat and mouse. An electron microscopic study. Z Zellforsch 136:97–110

  28. Vincent DS, Anand Kumar TC (1969) Electron microscopic studies on the pars intermedia of the ferret. Z Zellforsch 99:185–197

  29. Wingstrand KG (1966) Microscopic anatomy, nerve supply and blood supply of the pars intermedia. In: Harris GW, Donovan BT (eds) The pituitary gland. Butterworth and Company, London, Vol 3, pp 1–27

  30. Wittkowski W (1967) Synaptische Strukturen und Elementargranula in der Neurohypophyse des Meerschweinchens. Z Zellforsch 82:434–458

  31. Young BA (1977) Some observations on the ultrastructure of the stellate cells of the pars distalis of the guinea-pig. J Anat 124:153–156

  32. Young BA, Foster CL, Cameron E (1965) Some observations on the ultrastructure of the adenohypophysis of the rabbit. J Endocrinol 31:279–287

  33. Ziegler B (1963) Licht und elektronenmikroskopische Untersuchungen an Pars Intermedia und Neurohypophyse der Ratte. Z Zellforsch 59:486–506

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Correspondence to R. A. Perry.

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Perry, R.A., Robinson, P.M. & Ryan, G.B. Ultrastructure of the pars intermedia of the adult sheep hypophysis. Cell Tissue Res. 217, 211–223 (1981).

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Key words

  • Pituitary gland
  • Pars intermedia
  • Electron microscopy
  • Sheep