scholarly journals Electron Microscopic Observations on the Secretory Granules of the Adrenal Medulla of Domestic Fowl

1962 ◽  
Vol 23 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Hisao FUJITA ◽  
Mitsuo MACHINO
1982 ◽  
Vol 30 (7) ◽  
pp. 682-690 ◽  
Author(s):  
I M Varndell ◽  
F J Tapia ◽  
J De Mey ◽  
R A Rush ◽  
S R Bloom ◽  
...  

Enkephalin-like immunoreactivity has been localized to electron-dense secretory granules of cat and piglet carotid bodies and adrenal medullae, horse adrenal medulla, and also to human adrenal medulla and pheochromocytomas using a gold-labeled antibody technique performed at the electron microscopic level. The same granules were also demonstrated to exhibit dopamine-beta-hydroxylase-like immunoreactivity, which suggests a granular colocalization of amines and peptides in catecholamine-storing cells.


1968 ◽  
Vol 46 (5) ◽  
pp. 745-747 ◽  
Author(s):  
William W. L. Chang ◽  
Sergio A. Bencosme

A reevaluation of the silver methenamine reaction as an electron stain has ensued from recent use of glutaraldehyde fixation alone. By this technique, three cell types of rat adrenal medulla were found: (i) the norepinephrine-containing cells showed selectively stained, irregular, black granules; (ii) the epinephrine-containing cells showed round, light-grey granules; and (iii) the third cell type showed round granules like those of epinephrine-containing cells, but black in color, similar to those of the norepinephrine-containing cells.


1979 ◽  
Vol 16 (4) ◽  
pp. 395-404 ◽  
Author(s):  
H. Gelberg ◽  
G. L. Cockerell ◽  
R. R. Minor

The outer medullary (juxtacortical) zone of a normal equine adrenal gland had columnar chromaffin-positive cells arranged with their long axes perpendicular to fine vascular channels. The deeper medullary regions were composed of smaller irregularly round to polygonal chromaffin positive cells in small packets. Both cell types contained two types of membrane-bound cytoplasmic secretory granules. Osmiophilic granules with a homogeneous core, crenated membrane and narrow submembranous halo predominated in the columnar juxtacortical cells. The rounder, central medullary cells contained predominantly electron dense granules with a wide irregular electron lucent space between an eccentric core and the granule membrane. In contrast, irrespective of cell type or zone, cells from a pheochromocytoma contained only one type of granule similar to that described for the juxtacortical region of the normal equine adrenal medulla. The tumor cells could be classified into three subtypes based on density of granule packing but the granules were morphologically similar in all tumor cells.


Author(s):  
William J. Dougherty

The regulation of secretion in exocrine and endocrine cells has long been of interest. Electron microscopic and other studies have demonstrated that secretory proteins synthesized on ribosomes are transported by the rough ER to the Golgi complex where they are concentrated into secretory granules. During active secretion, secretory granules fuse with the cell membrane, liberating and discharging their contents into the perivascular spaces. When secretory activity is suppressed in anterior pituitary cells, undischarged secretory granules may be degraded by lysosomes. In the parathyroid gland, evidence indicates that the level of blood Ca ions regulates both the production and release of parathormone. Thus, when serum Ca is low, synthesis and release of parathormone are both stimulated; when serum Ca is elevated, these processes are inhibited.


1997 ◽  
Vol 45 (3) ◽  
pp. 425-436 ◽  
Author(s):  
Shigeyasu Tanaka ◽  
Takao Yora ◽  
Kazuhisa Nakayama ◽  
Kinji Inoue ◽  
Kazumasa Kurosumi

Using antibodies specific for pro-opiomelanocortin (POMC), amidated joining peptide (JP), and the prohormone convertase PC1, we showed immunocytochemically that PC1 in a corticotrophic tumor cell line, AtT-20, was co-localized either with POMC or with amidated JP in secretory granules, and also confirmed that POMC was cleaved mainly in secretory granules. Analysis using DAMP (3- [2,4-dinitroanilino]-3'-amino- N-methyldipropylamine) as the pH probe suggested a correlation between POMC processing and acidic pH in the secretory granules. Bafilomycin A1, a specific inhibitor of vacuolar-type H+-AT-Pase, completely inhibited POMC processing and caused constitutive secretion of the unprocessed precursor. By contrast, chloroquine, a weak base that is known to neutralize acidic organelles, was unable to inhibit POMC processing. Electron microscopic analysis revealed that, in AtT-20 cells treated with bafilomycin A1, the trans-Golgi cisternae were dilated and few secretory granules were present in the cytoplasm. These observations suggest that acidic pH provides a favorable environment for proteolytic processing of POMC by PC1 but is not required, and that integrity of the trans-Golgi network and sorting of POMC into secretory granules are important for POMC processing. (J Histochem Cytochem 45:425–436, 1997)


1996 ◽  
Vol 109 (10) ◽  
pp. 2453-2460 ◽  
Author(s):  
K. Fujimoto ◽  
M. Umeda ◽  
T. Fujimoto

We propose the use of membrane splitting by freeze-fracture for differential phospholipid analysis of protoplasmic and exoplasmic membrane leaflets (halves). Unfixed cells or tissues are quick-frozen, freeze-fractured, and platinum-carbon (Pt/C) shadowed. The Pt/C replicas are then treated with 2.5% sodium dodecyl sulfate (SDS) to solubilize unfractured membranes and to release cytoplasm or contents. While the detergent dissolves unfractured membranes, it would not extract lipids from split membranes, as their apolar domains are stabilized by their Pt/C replicas. After washing, the Pt/C replicas, along with attached protoplasmic and exoplasmic membrane halves, are processed for immunocytochemical labeling of phospholipids with antibody, followed by electron microscopic observation. Here, we present the application of the SDS-digested freeze-fracture replica labeling (SDS-FRL) technique to the transmembrane distribution of a major membrane phospholipid, phosphatidylcholine (PC), in various cell and intracellular membranes. Immunogold labeling revealed that PC is exclusively localized on the exoplasmic membrane halves of the plasma membranes, and the intracellular membranes of various organelles, e.g. nuclei, mitochondria, endoplasmic reticulum, secretory granules, and disc membranes of photoreceptor cells. One exception to this general scheme was the plasma membrane forming the myelin sheath of neurons and the Ca(2+)-treated erythrocyte membranes. In these cell membranes, roughly equal amounts of immunogold particles for PC were seen on each outer and inner membrane half, implying a symmetrical transmembrane distribution of PC. Initial screening suggests that the SDS-FRL technique allows in situ analysis of the transmembrane distribution of membrane lipids, and at the same time opens up the possibility of labeling membranes such as intracellular membranes not normally accessible to cytochemical labels without the distortion potentially associated with membrane isolation procedures.


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