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  • 1
    ISSN: 1432-0878
    Keywords: Growth-hormone cell ; Anterior pituitary ; Hepatectomy, rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural changes in pituitary growth-hormone cells were observed in partially hepatectomized rats. The hepatectomies were carried out during the afternoon after 3 p.m. The animals were sacrificed by decapitation at midnight at intervals of 32, 80, and 104 hours after the operation. The principal changes in the growth-hormone cells of anterior pituitary glands of partially hepatectomized rats were: (1) increased numbers of secretory granules in exocytosis, (2) increased numbers of microtubules, and (3) enlargement of endoplasmic reticulum and occurrence of dilated cisternae of the endoplasmic reticula. Many growth-hormone cells contained a reduced number of secretory granules. Exocytosis of growth-hormone granules was more frequently observed in animals sacrificed at 32 hours after the operation than in those killed at 80 or 104 hours after surgery. The above results in which appearance of numerous microtubules and active secretory granule extrusion in the growth-hormone cells were observed after hepatectomy indicate that ultrastructure of growth-hormone cells and growth hormone secretion were markedly stimulated by the operation.
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  • 2
    ISSN: 1432-0878
    Keywords: Pituitary ; Clonal cells ; Secretory granules ; Rat serum ; in vitro studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 2A8 clonal cells derived from the epithelium of Rathke's pouch of the fetal rat are essentially agranular when grown in vitro, in spite of their active secretion of hormones, i.e., ACTH, prolactin and growth hormone. These cells do not produce detectable amounts of thyrotrophic or gonadotrophic hormones in vitro. When the growth medium (Ham's F10) was supplemented with rat median eminence extract (MEE), l-thyroxin and fresh serum from hypophysectomized rats, some of the 2A8 cells accumulated and stored secretory granules which were characteristic of the cells of the intact pituitary gland. Typical thyrotrophic and gonadotrophic cells also became recognizable and all six anterior pituitary hormones were released into the culture medium. Growth of 2A8 cells in this modified culture medium resulted in an increased production of all hormones with increasing time in culture. These results indicate that the processes that lead to the accumulation of typical mature secretory granules which characterize the individual pituitary cell types are initiated or promoted by some unidentified factor or factors which are present in fresh rat serum. It is also apparent that fresh rat serum can promote the differentiation of gonadotrophs and thyrotrophs in vitro.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 202 (1979), S. 399-406 
    ISSN: 1432-0878
    Keywords: Castration cells ; Thyroidectomy cells ; LHRH ; TRH ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To investigate the relationship between LH-RH and TRH and the formation of castration cells and thyroidectomy cells, pituitary glands of 14-day old female rats were cultured with LH-RH or TRH for 10 days. Observed in these glands were external and internal zones, the former containing active, healthy appearing cells, and the latter consisting of many degenerative and necrotic cells. Gonadotrophs and thyrotrophs were readily demonstrated in the external zone of the organs by immunocytochemistry. Hypertrophie gonadotrophs (castration cells) and thyrotrophs (thyroidectomy cells) were observed only in the external zone by electron microscopy. Neither the typical signet-ring gonadotrophs nor intracisternal granules of thyroidectomy cells were seen in the present study. However, the hypertrophic gonadotrophs or thyrotrophs were similar to castration cells or thyroidectomy cells observed in the pituitary gland following castration or thyroidectomy. The results indicate that LH-RH and TRH directly stimulate the secretion of hormones and alter the morphological features of pituitary target cells.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 267 (1992), S. 519-523 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars anterior ; Corticotropes ; Adrenalectomy ; Reconstruction, 3D ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional form of corticotrophs in the anterior pitiutary gland of rats was studied by reconstruction from serial semi-thin sections both in control rats and rats one week after adrenalectomy. The corticotrophs have large depressions and cup-shaped cavities on their surface, and these features became more conspicuous after adrenalectomy. The hypertrophy of corticotrophs in adrenalectomized rats was quantified by measuring the area and perimeter of all serially sectioned profiles. The volume of the whole cell increased from 1129±114 μm3 to 2902±201 μm3 (P〈0.01) after adrenalectomy, while the surface area of the cells increased from 690±45 μm2 to 1431±116 μm2 (P〈0.01). The volume of the nucleus increased from 87±11 μm3 to 172±14 μm3 (P〈0.05). Though the complexity of the form of corticotrophs seems to be increased after adrenalectomy, the ratios (adrenalectomized/control) of cell volume and surface area were 2.57 and 2.07, respectively; this indicates that the increase of the cell volume was greater than that of the surface area.
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  • 5
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars anterior (distalis) ; Gonadotrophic cells, gonadotropes ; Thyrotropes ; Immunocytochemistry ; Suncus murinus (Insectivora)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract According to recent immunocytochemical studies of anterior pituitary cells, it is obvious that the “one cell-one hormone” theory must be modified. Many pituitary morphologists have demonstrated that there are some cells that contain two hormones. In this study, we demonstrate by means of immuno-electronmicroscopy the co-existence of gonadotrophins (FSH and LH) and thyrotrophin (TSH) in the same anterior pituitary cells of the musk shrew. These cells were remarkably altered in their ultrastructural features by either gonadectomy or thyroidectomy. Double labeling for gonadotrophins and thyrotrophin was present not only in the same cells but also in the same secretory granules. Our ability to demonstrate co-existence of gonadotrophins and thyrotrophin in the same cell may be due to our selection of fixative and embedding media for electron-microscopic immunocytochemistry. Our conclusion that gonadotrophins and thyrotrophin are produced in a single cell type of the anterior pituitary gland in the musk shrew, i.e., thyrogonadotrophs, suggests the need to consider a modification of the classic scheme for classification of anterior pituitary cells.
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  • 6
    ISSN: 1432-0878
    Keywords: Key words: Luteinizing hormone (LH) ; Lung ; Bronchi ; bronchioli ; Stomach ; Pituitary gland ; Embryo ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Luteinizing hormone (LH) immunoreactivity was detected in the lung and stomach of chick embryos by the immunoperoxidase staining technique using specific antiserum to chicken LH. Immunoreactive LH (ir-LH) cells first appeared in the primordial cells of the epithelial layer of lung bud and foregut as well as of Rathke’s pouch in the 3-day-old embryo, Hamburger and Hamilton stage 21. Ir-LH cells increased in number with advancing age of embryos in the lung, stomach, and pituitary gland. In the lung of 7-day-old embryos, stage 31, the ir-LH cells were distributed in the epithelium of primary, secondary, and tertiary bronchi, and their shapes were pseudostratified columnar, simple columnar, and simple cuboidal, depending on their sites in the intrapulmonary airway. Ir-LH cells were more numerous in the median part than in the lateral part of the lung, and the population in the epithelial layer of entobronchi of the secondary bronchi was 4 times higher than that in ectobronchi and laterobronchi of the secondary bronchi and in the primary bronchi. The immunoreactive products were found, either in the entire cell or in the apical part, facing the lumina of bronchi. In the stomach, ir-LH cells were found in the epithelial layer of gastric glands. No ir-LH cells were observed in interstitial regions, which consisted of mesenchymal cells and blood vessels, in the lung and stomach tissues. With advancing age, ir-LH cells changed their shapes to flat or squamous, coincident with the formation of parabronchi. Other pituitary hormones were not observed immunohistochemically in either the lung or stomach before hatching. Preabsorption of the antiserum against avian LH with the purified chicken LH or the extract of pituitaries from 10-day-old embryos completely destroyed the immunoreactivity to the cells in the lung and the pituitary. A single band of the immunoreaction products, whose molecular weight was around 25 K daltons, was shown by the immunostaining of nitrocellulose membrane transblotted after sodium dodecylsulphate-polyacrylamide gel electrophoresis of the purified pituitary LH, extracts of pituitaries from 10-day-old embryos, and the extracts of lungs from 7-, 10-, and 14-day-old chick embryos. These results demonstrated that ir-LH cells are present in extrapituitary tissues, and may play an important role during the development of chick embryonic lung and stomach.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 201 (1979), S. 93-99 
    ISSN: 1432-0878
    Keywords: Pituitary cell ; Gonadotrophs ; Culture ; Cell lines ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gonadotroph-rich cell lines were established from multipotential pituitary clonal cells (2A8) which were implanted under kidney capsule of hypophysectomized female rats. These cell lines secrete gonadotrophins (FSH and LH) continuously over two months after establishment; LHRH stimulated the secretion of hormones into the culture medium. Many of the cells reacted immunohistochemically to antiserum to FSH or LH, while a small number reacted to antiserum to prolactin or TSH. They did not contain normal secretory granules such as those of gonadotrophs in vivo.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 189 (1978), S. 31-40 
    ISSN: 1432-0878
    Keywords: Pituitary cell clone ; LHRH-Sepharose ; Gonadotrophs ; Hypertrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 2A8 clonal cells derived from the epithelium of Rathke's pouch of fetal rats were cultured in growth medium supplemented with fresh rat serum, median-eminence extract and l-thyroxine. Then, in order to isolate gonadotrophs, cyanogen bromide-activated Sepharose which was conjugated with LHRH (LHRH-Sepharose) was added to the culture medium. Fourteen days after incubation of 2A8 cells with LHRH-Sepharose, agranular and granular cells were rapidly bound to LHRH-Sepharose when fresh serum had previously been added in the medium. The cytoplasm of granular cells that were bound to LHRH-Sepharose contained spherical secretory granules (200–250 nm in diameter). These cells were similar in morphology to the FSH and LH gonadotrophs described by Kurosumi (1968). Moreover, many of them appeared as hypertrophied cells that resembled “castration” cells. These results demonstrate that LHRH conjugated to Sepharose can be used to separate gonadotrophs from other 2A8 cells, and it is suggested that the hypertrophy of some cells might be due to persistent stimulation by LHRH which is likely bound to receptors on the cell membrane.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 242 (1985), S. 179-183 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars anterior ; Prolactin cells ; Secretory granules ; Thyroxine ; Thyroidectomy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the anterior pituitary glands of neonatally thyroidectomized female rats sacrificed at 30 days of age, the prolactin granules were small and spherical in shape. The administration of thyroxine to neonatally thyroidectomized rats produced an obvious increase in the number and size of secretory granules in prolactin cells; comparatively large, pleomorphic secretory granules were frequently observed in these cells. These enlarged and pleomorphic granules closely resembled those observed in the prolactin cells of sham-operated control rats. These results may indicate that thyroxine stimulates the basic metabolism or cellular function of prolactin cells of neonatally thyroidectomized rats and leads to the formation of prolactin granules that are similar to those of shamoperated control rats.
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  • 10
    ISSN: 1432-0878
    Keywords: Secretory granules ; GH cells ; Anterior pituitary ; Musk shrew ; Suncus murinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Unique rod-shaped secretory granules were observed among oval or spherical secretory granules in GH cells of the anterior pituitary gland of musk shrew using the protein A-gold procedure combined with electron microscopy. The rod-shaped and spherical secretory granules were both immunoreactive by the immuno-gold method using antiserum to sheep GH. The rod-shaped secretory granules, which seem to be formed directly from the Golgi vesicles, extend from several hundred to several thousand nm in length. They often touch each other and fuse. The spherical secretory granules are also unique in that they may also fuse with loss of dense contents to leave “empty” circular membrane profiles in the cytoplasm. Both the rodshaped and spherical secretory granules are secreted from the cell by exocytosis.
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