scholarly journals FURTHER STUDIES ON THE THETA CELL OF THE MOUSE ANTERIOR PITUITARY AS REVEALED BY ELECTRON MICROSCOPY, WITH SPECIAL REFERENCE TO THE MODE OF SECRETION

1962 ◽  
Vol 15 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Masao Sano
Keyword(s):  
Cell Membrane ◽  
Anterior Pituitary ◽  
Amorphous Materials ◽  
Distal Part ◽  
Secretory Granules ◽  
Complete Loss ◽  
Low Density ◽  
Cell Type ◽  
Golgi Vesicles ◽  
Golgi Region

Theta cells reported previously as a new cell type in the anterior pituitary of the mouse were examined with the electron microscope. This type of cell is distinguished by the presence of pleomorphic secretory granules, a characteristic arrangement of the rough surfaced variety of endoplasmic reticulum, a well developed Golgi complex, and an eccentrically located nucleus. The secretory granules are seen at first as small granules of low density within the Golgi vesicles. While they are within the Golgi vesicles they become larger and denser. Simultaneously they move from the proximal to the distal part of the Golgi region and finally emerge from the Golgi area as mature granules in the cytoplasm. Thus, secretory granules are always enveloped by a limiting membrane which originates from the wall of the Golgi vesicle. At the stage of granule-extrusion, the cell membrane fuses with the limiting membrane of the granules and openings in the cell membrane appear at the place of extrusion. The granules then appear to lie within inpocketings of the cell membrane. They lose their density within these inpocketings or within the cytoplasm and occasionally show fragmentation. After complete loss of density, the granules are extruded as amorphous materials to the territory outside of the cell.

scholarly journals Cell Type-Specific Metabolism of Peptidylglycineα -Amidating Monooxygenase in Anterior Pituitary*

Endocrinology ◽  
2000 ◽  
Vol 141 (8) ◽  
pp. 3020-3034 ◽  
Author(s):  
Rajaa El Meskini ◽  
Richard E. Mains ◽  
Betty A. Eipper
Keyword(s):  
Anterior Pituitary ◽  
Secretory Granules ◽  
Primary Cultures ◽  
Cell Types ◽  
Pituitary Cell ◽  
Male Rat ◽  
Pituitary Cells ◽  
Cell Type ◽  
Cell Content ◽  
Monooxygenase Activity

Peptidylglycine α-amidating monooxygenase (PAM) is a bifunctional enzyme expressed in each major anterior pituitary cell type. We used primary cultures of adult male rat anterior pituitary to examine PAM expression, processing, and secretion in the different pituitary cell types and to compare these patterns to those observed in transfected AtT-20 corticotrope tumor cells. Immunostaining and subcellular fractionation identified PAM in pituitary secretory granules and additional vesicular compartments; in contrast, in AtT-20 cells, transfected PAM was primarily localized to the trans-Golgi network. PAM expression was highest in gonadotropes, with moderate levels in somatotropes and thyrotropes and lower levels in corticotropes and lactotropes. Under basal conditions, less than 1% of the cell content of monooxygenase activity was secreted per h, a rate comparable to the basal rate of release of individual pituitary hormones. General secretagogues stimulated PAM secretion 3- to 5-fold. Stimulation with specific hypothalamic releasing hormones demonstrated that different pituitary cell types secrete characteristic sets of PAM proteins. Gonadotropes and thyrotropes release primarily monofunctional monooxygenase. Somatotropes secrete primarily bifunctional PAM, whereas corticotropes secrete a mixture of mono- and bifunctional proteins. As observed in transfected AtT-20 cells, pituitary cells rapidly internalize the PAM/PAM-antibody complex from the cell surface. The distinctly different steady-state localizations of endogenous PAM in primary pituitary cells and transfected PAM in AtT-20 cell lines may simply reflect the increased storage capacity of primary pituitary cells.

scholarly journals Immunocytochemical Localization of the Prohormone Convertases PC1 and PC2 in Rat Prolactin Cells

1998 ◽  
Vol 46 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Laurent Muller ◽  
Renée Picart ◽  
Alain Barret ◽  
Nabil G. Seidah ◽  
Claude Tougard
Keyword(s):  
Anterior Pituitary ◽  
Biochemical Analysis ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Specific Protein ◽  
Cell Type ◽  
Prolactin Cells ◽  
Prohormone Convertases ◽  
New Information ◽  
Peptide Precursor

The prohormone convertases PC1 and PC2 are subtilisin-related endopepti-dases that process prohormone and neuropeptide precursors. Using different ultrastructural immunocytochemical approaches, we have investigated their intracellular distribution in a neuroendocrine cell type that has not been examined thus far, the rat anterior pituitary lactotrope. These cells secrete mainly prolactin and also express the neuroendocrine-specific protein secretogranin II, which is considered a peptide precursor. Our study provides evidence for the expression of PC1 and PC2 in rat lactotropes and provides new information on their subcellular localization. Apart from their presence in the secretory granules, PC1 and PC2 displayed different major localization along the secretory pathway. PC1 immunoreactivity was concentrated in the Golgi apparatus, whereas PC2 immunoreactivity was prominent in the rough endoplasmic reticulum (RER). These observations provide morphological support for previous biochemical analysis of proPC1 and proPC2 post-translational processing, which has demonstrated that PC1 exits very rapidly from the RER, whereas PC2 is retained much longer in this compartment.

scholarly journals Sorting of three secretory proteins to distinct secretory granules in acidophilic cells of cow anterior pituitary.

1987 ◽  
Vol 105 (4) ◽  
pp. 1579-1586 ◽  
Author(s):  
S Hashimoto ◽  
G Fumagalli ◽  
A Zanini ◽  
J Meldolesi
Keyword(s):  
Anterior Pituitary ◽  
Secretory Granules ◽  
Pituitary Cell ◽  
The Other ◽  
Secretory Proteins ◽  
Frozen Sections ◽  
Sparse Labeling ◽  
Golgi Region ◽  
Ultrathin Frozen Sections ◽  
Double Immunolabeling

The distribution of three proteins discharged by regulated exocytosis--growth hormone (GH), prolactin (PRL), and secretogranin II (SgII)--was investigated by double immunolabeling of ultrathin frozen sections in the acidophilic cells of the bovine pituitary. In mammotrophs, heavy PRL labeling was observed over secretory granule matrices (including the immature matrices at the trans Golgi surface) and also over Golgi cisternae. In contrast, in somatotrophs heavy GH labeling was restricted to the granule matrices; vesicles and tubules at the trans Golgi region showed some and the Golgi cisternae only sparse labeling. All somatotrophs and mammotrophs were heavily positive for GH and PRL, respectively, and were found to contain small amounts of the other hormone as well, which, however, was almost completely absent from granules, and was more concentrated in the Golgi complex, admixed with the predominant hormone. Mixed somatomammotrophs (approximately 26% of the acidophilic cells) were heavily positive for both GH and PRL. Although admixed within Golgi cisternae, the two hormones were stored separately within distinct granule types. A third type of granule was found to contain SgII. Spillage of small amounts of each of the three secretory proteins into granules containing predominantly another protein was common, but true intermixing (i.e., coexistence within single granules of comparable amounts of two proteins) was very rare. It is concluded that in the regulated pathway of acidophilic pituitary, cell mechanisms exist that cause sorting of the three secretory proteins investigated. Such mechanisms operate beyond the Golgi cisternae, possibly at the sites where condensation of secretion products into granule matrices takes place.

scholarly journals THE FINE STRUCTURE OF VON EBNER'S GLAND OF THE RAT

1970 ◽  
Vol 44 (2) ◽  
pp. 340-353 ◽  
Author(s):  
Arthur R. Hand
Keyword(s):  
Fine Structure ◽  
Cell Membrane ◽  
Golgi Complex ◽  
Secretory Granules ◽  
Myoepithelial Cells ◽  
Duct Cells ◽  
Golgi Region ◽  
Granule Membrane ◽  
Cytological Features ◽  
Basal Portion

The fine structure of von Ebner's gland was studied in untreated rats and rats stimulated to secrete by fasting-refeeding or injection of pilocarpine. Cytological features were similar to those reported for pancreas and parotid gland. Abundant granular endoplasmic reticulum filled the basal portion of the cell, a well-developed Golgi complex was located in the vicinity of the nucleus, and the apical portion of the cell was filled with dense secretory granules. Dense heterogeneous bodies resembling lysosomes were closely associated with the Golgi complex. Coated vesicles were seen in the Golgi region and also in continuity with the cell membrane. Granule discharge occurred by fusion of the granule membrane with the cell membrane at the secretory surface. Successive fusion of adjacent granules to the previously fused granule formed a connected string of granules in the apical cytoplasm. Myoepithelial cells were present within the basement membrane, and nerve processes were seen adjacent to acinar and myoepithelial cells. Duct cells resembled the intercalated duct cells of the major salivary glands.

Cell Membrane-Coated Electrospun Fibers Enhance Keratinocyte Growth through Cell-Type Specific Interactions

2021 ◽  
Author(s):  
Wai Hon Chooi ◽  
Quanbin Dong ◽  
Jeremy Zhi Yan Low ◽  
Clement Yuen ◽  
Jiah Shin Chin ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Electrospun Fibers ◽  
Specific Interactions ◽  
Cell Type ◽  
Cell Type Specific

scholarly journals DEVELOPMENT OF ENDOGENOUS PEROXIDASE IN FETAL RAT SUBMANDIBULAR GLAND

1973 ◽  
Vol 21 (1) ◽  
pp. 42-50 ◽  
Author(s):  
SHOHEI YAMASHINA ◽  
TIBOR BARKA
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Submandibular Gland ◽  
Rough Endoplasmic Reticulum ◽  
Peroxidase Activity ◽  
Secretory Granules ◽  
Prenatal Development ◽  
Reaction Products ◽  
Cell Type ◽  
Endogenous Peroxidase

The prenatal development of endogenous peroxidase activity in the submandibular gland of rat was investigated by means of the diaminobenzidine-H2O2 histochemical method. The submandibular gland of a 16-day-old fetus was composed of cords of uniform, undifferentiated cells which contained no secretory granules and revealed no peroxidase activity. Peroxidase activity first appeared at the 17th day of gestation in the cisternae of the rough endoplasmic reticulum and nuclear envelope in a few cells. At the 18th day of gestation cells which exhibited reaction products in the rough endoplasmic reticulum and nuclear envelope also contained secretory granules with a strong peroxidase activity. During the last days of gestation the number of peroxidase positive cells, which contained numerous secretory granules, increased. The peroxidase-containing cells are the immediate precursors of the proacinar cells of early postnatal stages. During the same time period, when the peroxidase-containing cells differentiated, a second cell type also differentiated in the cellular cords. The development of this cell type was marked by the appearance of secretory granules stainable with toluidine blue. Through the prenatal development, this cell type revealed no peroxidase activity and was identified with the terminal tubule cell of the newborn. The morphologic and cytochemical findings indicate that terminal tubule cells and proacinar cells are committed cells; the former differentiate toward 2nd order intercalated duct cells and the latter transform to mature acinar cells.

Non-contact-based determination of membrane permeability to water and dimethyl sulfoxide of cells virtually trapped in a self-induced micro-vortex

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Hsiu-Yang Tseng ◽  
Chiu-Jen Chen ◽  
Zong-Lin Wu ◽  
Yong-Ming Ye ◽  
Guo-Zhen Huang
Keyword(s):  
Cell Membrane ◽  
Dimethyl Sulfoxide ◽  
Membrane Permeability ◽  
Cell Membrane Permeability ◽  
Cell Type ◽  
Cryoprotective Agents ◽  
A Cell

Cell-membrane permeability to water (Lp) and cryoprotective agents (Ps) of a cell type is a crucial cellular information for achieving optimal cryopreservation in the biobanking industry. In this work, a...

Synaptobrevin isoforms in secretory granules and synaptic-like microvesicles in anterior pituitary cells

Life Sciences ◽  
1998 ◽  
Vol 62 (7) ◽  
pp. 607-616 ◽  
Author(s):  
Glòria Majó ◽  
Fernando Aguado ◽  
Juan Blasi ◽  
Jordi Marsal
Keyword(s):  
Anterior Pituitary ◽  
Secretory Granules ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells
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