High resolution analysis of the secretory pathway in mammotrophs of the rat anterior pituitary.

M M Salpeter; M G Farquhar

doi:10.1083/jcb.91.1.240

High resolution analysis of the secretory pathway in mammotrophs of the rat anterior pituitary.

The Journal of Cell Biology ◽

10.1083/jcb.91.1.240 ◽

1981 ◽

Vol 91 (1) ◽

pp. 240-246 ◽

Cited By ~ 29

Author(s):

M M Salpeter ◽

M G Farquhar

Keyword(s):

High Resolution ◽

Golgi Complex ◽

Secretory Granules ◽

Female Rats ◽

Secretory Process ◽

Pituitary Cells ◽

Secretory Product ◽

Electron Microscope Autoradiography ◽

New Findings ◽

Density Analysis

The secretory process in pituitary mammotrophs was analyzed by quantitative electron microscope autoradiography. Dispersed pituitary cells from estrogen-treated female rats were subjected to pulse-labeling with [3H]leucine (5 min) followed by a chase incubation of up to 4 h. Autoradiograms were prepared using fine-grained emulsion (Kodak 129-01), and analyzed using a three-step "mask analysis' procedure: (a) the distribution of autoradiographic grains is determined as in a simple grain density analysis; (b) masks (transparent overlays) are used to generate expected grains from assumed sources; and (c) a computer program compares these two distributions and varies the expected distribution to match the observed distribution, thereby identifying the radioactive sources in the tissue. The overall route of intracellular transport of prolactin from rough endoplasmic reticulum (ER) leads to Golgi complex leads to immature secretory granules leads to mature secretory granules was as established in previous studies. However, by use of the high resolution emulsion and method of analysis, the precision with which label could be localized within individual source compartments was much greater and the time resolution was much sharper than achieved previously using Ilford L4 emulsion and simple grain density analysis. The main new findings were as follows: (a) the ER was essentially drained of radioactivity by 30 min, the Golgi complex by 1 h, and the immature secretory granules by 2h postpulse. This indicates that the secretory product (prolactin) is rapidly and efficiently transported out of these compartments. (b) approximately 30% of the total radioactivity remains located in the ground cytoplasm over the entire postpulse period examined (up to 4 h), and by 30 min postpulse the grain density in the ground cytoplasm exceeded that of the ER. This indicates the ability to resolve ER-associated label (presumably associated mainly with secretory products) from the cytoplasmic label (presumably associated with nonsecretory proteins). (c) the specific activity of immature secretory granules was much greater than previously appreciated; at 1 h postpulse it was greater than 200 times that of the adjacent Golgi complex cisternae. This large dynamic range in observed grain density demonstrates the ability to effectively correct for radiation spread and thus to detect with great accuracy high concentration of label even from very small structures (20-100 nm) which constitute a small percentage (less than 1%) of the total cell area.

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Ultrastructural Aspects of Golgi Complex Function in Parathyroid Cells of Winter Frogs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073842 ◽

1973 ◽

Vol 31 ◽

pp. 680-681

Author(s):

William J. Dougherty

Keyword(s):

Golgi Complex ◽

Secretory Granules ◽

Complex Function ◽

Secretory Activity ◽

Secretory Proteins ◽

Perivascular Spaces ◽

Pituitary Cells ◽

Electron Microscopic ◽

Ca Ions ◽

Regulation Of Secretion

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.

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Lectin-labeled membrane is transferred to the Golgi complex in mouse pituitary cells in vivo.

Journal of Histochemistry & Cytochemistry ◽

10.1177/35.4.2434560 ◽

1987 ◽

Vol 35 (4) ◽

pp. 489-498 ◽

Cited By ~ 11

Author(s):

B J Balin ◽

R D Broadwell

Keyword(s):

Golgi Complex ◽

Secretory Granules ◽

Surface Membrane ◽

Dense Core ◽

Secretory Cells ◽

Pituitary Cells ◽

Posterior Pituitary ◽

Peroxidase Reaction ◽

Mouse Pituitary

Labeling of the Golgi complex with the lectin conjugate wheat germ agglutinin-horseradish peroxidase (WGA-HRP), which binds to cell surface membrane and enters cells by adsorptive endocytosis, was analyzed in secretory cells of the anterior, intermediate, and posterior lobes of mouse pituitary gland in vivo. WGA-HRP was administered intravenously or by ventriculo-cisternal perfusion to control and salt-stressed mice; post-injection survival times were 30 min-24 hr. Peroxidase reaction product was identified within the extracellular clefts of anterior and posterior pituitary lobes through 24 hr but was absent in intermediate lobe. Endocytic vesicles, spherical endosomes, tubules, dense and multivesicular bodies, the trans-most saccule of the Golgi complex, and dense-core secretory granules attached or unattached to the trans Golgi saccule were peroxidase-positive in the different types of anterior pituitary cells and in perikarya of supraoptico-neurohypophyseal neurons; endoplasmic reticulum and the cis and intermediate Golgi saccules in the same cell types were consistently devoid of peroxidase reaction product. Dense-core secretory granules derived from cis and intermediate Golgi saccules in salt-stressed supraoptic perikarya likewise failed to exhibit peroxidase reaction product. The results suggest that in secretory cells of anterior and posterior pituitary lobes, WGA-HRP, initially internalized with cell surface membrane, is eventually conveyed to the trans-most Golgi saccule, in which the lectin conjugate and associated membrane are packaged in dense-core secretory granules for export and potential exocytosis of the tracer. Endoplasmic reticulum and the cis and intermediate Golgi saccules appear not to be involved in the endocytic/exocytic pathways of pituitary cells exposed to WGA-HRP.

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Three-dimensional architecture of Golgi apparatus in the hormone secretory cell

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100085563 ◽

1991 ◽

Vol 49 ◽

pp. 252-253

Author(s):

S. Tai ◽

R.M. Albrecht

Keyword(s):

Golgi Apparatus ◽

Golgi Complex ◽

Secretory Cell ◽

Secretory Granules ◽

Three Dimensional ◽

Cell Types ◽

Pituitary Cells ◽

Golgi Stack ◽

Secretory Products ◽

Cell Fractions

The Golgi apparatus plays an important role in the process of packaging and sorting of secretory granules in endocrine and exocrine cells. The intra Golgi site for concentrating secretory materials, packaging, and sorting the secretory granules has been widely studied using cytochemical, immunocytochemical and biochemical methods on cells and cell fractions. It is generally accepted that the secretory products fo How the cis to trans pathway across the Golgi stack. Within the Golgi complex, secretory products appear to be concentrated in the dilated rims of the trans-most cisternae which are associated with the formation of secretory granules. In pituitary cells the organization of the Golgi apparatus is not as regular as that described for many other cell types. The cisternae of different Golgi stacks are irregular in size and shape. The cis-trans arrangement is not in a definitive orientation.

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A Study of Granule Formation in the Bat Parafollicular Cell

Journal of Cell Science ◽

10.1242/jcs.5.2.531 ◽

1969 ◽

Vol 5 (2) ◽

pp. 531-559

Author(s):

E. A. NUNEZ ◽

R. P. GOULD ◽

S. J. HOLT

Keyword(s):

Endoplasmic Reticulum ◽

Golgi Complex ◽

Secretory Granules ◽

Granular Endoplasmic Reticulum ◽

Secretory Product ◽

Central Mass ◽

Granule Formation ◽

Cytoplasmic Matrix ◽

Parafollicular Cell ◽

Parafollicular Cells

The fine structure of the bat thyroid parafollicular cell has been examined at monthly intervals throughout the hibernating period. During November and December parafollicular cells appear either partly or totally degranulated and intact dense secretory granules are relatively sparse. The degranulated cells exhibit an inconspicuous Golgi complex and relatively few lysosome-type bodies. Few degranulated parafollicular cells are present in thyroid glands from bats collected in January. When found they are characterized by the presence of whorls of cytoplasmic agranular membranes which enclose a central mass of cellular debris. January bat thyroids are characterized by the presence of three different types of parafollicular cell. One type contains no secretory granules. The cytoplasmic matrix of this type is rich in granular endoplasmic reticulum and free ribosomes and its small Golgi complex consists of several slightly dilated saccules. In close proximity to the Golgi complex are numerous small to medium-sized vesicles which often appear to merge with Golgi elements. Such vesicles are considered to represent the vehicle by which secretory product is transferred from the endoplasmic reticulum to the Golgi complex. The second type of parafollicular cell differs from the first in containing large numbers of intact dense secretory granules. It is also characterized by an extensive Golgi complex which appears to be forming new secretory granules, and by a less extensive granular endoplasmic reticulum. The third type of parafollicular cell shows a structure intermediate between the first two. The cytoplasm of all three types of January parafollicular cells contains many structures belonging to the lysosomal-vacuolar system, including autophagic vacuoles, vacuolated dense bodies and multivesicular bodies. By February and March only parafollicular cells of type 2 are observed. They contain few lysosome-like structures. It is concluded that during mid-hibernation (January), parafollicular cells undergo a series of intracellular changes during which new dense secretory granules are produced. Accompanying granule formation is an augmentation of lysosome-like structures which probably serve as a means of digesting debris from previous secretory cycles.

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A Cytological Study of the Alimentary Tract of the Domestic Fowl Gallus Domesticus

Journal of Cell Science ◽

10.1242/jcs.s3-88.4.419 ◽

1947 ◽

Vol s3-88 (4) ◽

pp. 419-443

Author(s):

K. S. CHODNIK

Keyword(s):

Alimentary Tract ◽

Morphological Changes ◽

Secretory Granules ◽

Close Association ◽

Secretory Activity ◽

Secretory Process ◽

Surface Epithelium ◽

Secretory Product ◽

New Production ◽

Gastric Cells

1. Proventriculus The Golgi material of all the gastric cells, except the zymogenic cells, is situated between the nucleus and the lumen of the gland. In the zymogenic cells it always lies at the level of the bottom of the intercellular clefts. The apparent reversal of the polarity of the Golgi material of the zymogenic cells is due to the movement of the nucleus. The mitochondria of the surface epithelium and the mucous neck cells are very delicate filaments. In the zymogenic cells thick rods and granules are usual. The functional stage is characterized by the presence of long rods with marked polar orientation. Secretory granules arise in close association with the Golgi material of all the gastric cells. Feeding accelerates the evacuation of secretion and immediately stimulates new production. A total expulsion of secretory granules never takes place in any of the gastric cells. 2. Gizzard The keratinoid material is a secretory product. The Golgi material does not undergo any changes after feeding. The secretory process is very slow and is independent of digestion. Secretion terminates with the degeneration and ultimate death of the cell. 3. Intestinal epithelium The Golgi material of the epithelial cells lies above the nucleus. It shows marked changes of morphological and physico-chemical nature as soon as the resting cell is stimulated by direct contact with food. The mitochondria are in the form of filaments, rods, and granules. Their polar arrangement is a constant feature. When the cell is first stimulated by food, the mitochondria stain very faintly. Secretory granules arise in close association with the Golgi material; they move towards the glandular pole of the cell. Morphological changes of the Golgi material and mitochondria diminish and finally disappear in the posterior parts of the alimentary tract. 4. Goblet cells The Golgi material lies above the nucleus. During secretory activity it enlarges greatly; it decreases in mass during the final stage of secretion. The mitochondria are in the form of filaments, rods, and granules. With, the accumulation of secretory material, the mitochondria collect on the border of the mucous mass and in the cytoplasm of the narrow part of the cell. Secretory granules arise in close association with the Golgi material. The secretory process of these cells is autonomous and is not directly correlated with digestion.

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The Ultrastructure of Lymphocytic Hypophysitis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098824 ◽

1981 ◽

Vol 39 ◽

pp. 466-467

Author(s):

S.L. Asa ◽

K. Kovacs ◽

J. M. Bilbao ◽

R. G. Josse ◽

K. Kreines

Keyword(s):

Electron Microscopy ◽

Plasma Cells ◽

Secretory Granules ◽

Sella Turcica ◽

Uranyl Acetate ◽

Lymphocytic Hypophysitis ◽

Pituitary Cells ◽

Transmission Electron ◽

Ultrathin Sections ◽

Mass Lesions

Seven cases of lymphocytic hypophysitis in women have been reported previously in association with various degrees of hypopituitarism. We report two pregnant patients who presented with mass lesions of the sella turcica, clinically mimicking pituitary adenoma. However, pathologic examination revealed extensive infiltration of the anterior pituitary by lymphocytes and plasma cells with destruction of the gland. To our knowledge, the ultrastructural features of lymphocytic hypophysitis have not been studied so far.For transmission electron microscopy, tissue from surgical specimens was fixed in glutaraldehyde, postfixed in OsO4, dehydrated and embedded in epoxy-resin. Ultrathin sections were stained with uranyl acetate and lead citrate and examined with a Philips 300 electron microscope.Electron microscopy revealed adenohypophysial cells of all types exhibiting varying degrees of injury. In the areas of most dense inflammatory cell infiltration pituitary cells contained large lysosomal bodies fusing with secretory granules (Fig. 1), as well as increased numbers of swollen mitochondria, indicating oncocytic transformation (Fig. 2).

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Effects of in vivo gonadal hormone environment on in vitro hGRF-40-stimulated GH release

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1985.249.3.e276 ◽

1985 ◽

Vol 249 (3) ◽

pp. E276-E280 ◽

Cited By ~ 3

Author(s):

W. S. Evans ◽

R. J. Krieg ◽

E. R. Limber ◽

D. L. Kaiser ◽

M. O. Thorner

Keyword(s):

Female Rats ◽

Male Rats ◽

Gonadal Hormone ◽

Base Line ◽

Pituitary Cells ◽

Intact Male ◽

Castrate Male ◽

Basal Release

The effects of gender and the gonadal hormone environment on basal and stimulated growth hormone (GH) release by dispersed and continuously perifused rat anterior pituitary cells were examined. Cells from intact male and diestrus day 2 female rats and from castrate male rats either untreated or treated with testosterone (T) or 17 beta-estradiol (E2) were used. Basal GH release (ng/min per 10(7) cells; mean +/- SE) by cells from diestrus day 2 female rats was less than by cells from castrate rats treated with T (4.3 +/- 0.6 vs. 11.4 +/- 2.7, respectively; P less than 0.025). No other differences in basal release were detected. Concentration-response relationships were documented between human GH-releasing factor 40 (hGRF-40; 0.03-100 nM given as 2.5-min pulses every 27.5 min) and GH release. Mean (+/- SE) overall GH release (ng/min per 10(7) cells) above base line was greater by cells from intact male rats (496 +/- 92) than by cells from castrate (203 +/- 37.3; P less than 0.0001), castrate and T-treated (348 +/- 52.8; P = 0.008), or castrate and E2-treated (58.1 +/- 6.8; P less than 0.001) male rats or by diestrus day 2 rats (68.6 +/- 9.5; P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

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Redistribution of a rab3-like GTP-binding protein from secretory granules to the Golgi complex in pancreatic acinar cells during regulated exocytosis

The Journal of Cell Biology ◽

10.1083/jcb.124.1.43 ◽

1994 ◽

Vol 124 (1) ◽

pp. 43-53 ◽

Cited By ~ 54

Author(s):

BP Jena ◽

FD Gumkowski ◽

EM Konieczko ◽

GF von Mollard ◽

R Jahn ◽

...

Keyword(s):

Plasma Membrane ◽

Golgi Complex ◽

Binding Protein ◽

Secretory Granules ◽

Acinar Cells ◽

Pancreatic Acinar Cells ◽

Apical Plasma Membrane ◽

Gtp Binding Protein ◽

Regulated Exocytosis ◽

Gtp Binding

Regulated secretion from pancreatic acinar cells occurs by exocytosis of zymogen granules (ZG) at the apical plasmalemma. ZGs originate from the TGN and undergo prolonged maturation and condensation. After exocytosis, the zymogen granule membrane (ZGM) is retrieved from the plasma membrane and ultimately reaches the TGN. In this study, we analyzed the fate of a low M(r) GTP-binding protein during induced exocytosis and membrane retrieval using immunoblots as well as light and electron microscopic immunocytochemistry. This 27-kD protein, identified by a monoclonal antibody that recognizes rab3A and B, may be a novel rab3 isoform. In resting acinar cells, the rab3-like protein was detected primarily on the cytoplasmic face of ZGs, with little labeling of the Golgi complex and no significant labeling of the apical plasmalemma or any other intracellular membranes. Stimulation of pancreatic lobules in vitro by carbamylcholine for 15 min, resulted in massive exocytosis that led to a near doubling of the area of the apical plasma membrane. However, no relocation of the rab3-like protein to the apical plasmalemma was seen. After 3 h of induced exocytosis, during which time approximately 90% of the ZGs is released, the rab3-like protein appeared to translocate to small vesicles and newly forming secretory granules in the TGN. No significant increase of the rab3-like protein was found in the cytosolic fraction at any time during stimulation. Since the protein is not detected on the apical plasmalemma after stimulation, we conclude that recycling may involve a membrane dissociation-association cycle that accompanies regulated exocytosis.

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