scholarly journals STIMULATION OF GLUCOSE-6-PHOSPHATASE ACTIVITY IN THE MUCOSAL CELLS OF THE MOUSE INTESTINE

1973 ◽  
Vol 21 (5) ◽  
pp. 426-440 ◽  
Author(s):  
J. S. HUGON ◽  
D. MAESTRACCI ◽  
D. MÉNARD
Keyword(s):  
Endoplasmic Reticulum ◽  
Phosphatase Activity ◽  
Smooth Endoplasmic Reticulum ◽  
Male Mice ◽  
Dense Bodies ◽  
Absorptive Cells ◽  
Mucosal Cells ◽  
Mouse Intestine ◽  
Stimulation Of

Adult Swiss ICR male mice were fed fructose or glucose for several days. Glucose-6-phosphatase activity in the duodenal and jejunal epithelium was measured by biochemical and cytophotometric means, and it was also localized cytochemically. The fructose diet stimulated glucose-6-phosphatase activity within 6 hr of feeding. The enzyme was stimulated more in the absorptive cells of the basal third than in those of the median and apical third of the villi. After 3 days of feeding of fructose, the smooth endoplasmic reticulum hypertrophied and occupied large areas in the absorptive cells. Lipoprotein spherules and polymorphic dense bodies were also observed. No such modifications were seen in glucose-fed animals.

scholarly journals DIFFERENTIATION OF ENDOPLASMIC RETICULUM IN HEPATOCYTES

1971 ◽  
Vol 49 (2) ◽  
pp. 264-287 ◽  
Author(s):  
A. Leskes ◽  
P. Siekevitz ◽  
G. E. Palade
Keyword(s):  
Endoplasmic Reticulum ◽  
Phosphatase Activity ◽  
Rough Endoplasmic Reticulum ◽  
Specific Activity ◽  
Smooth Endoplasmic Reticulum ◽  
Rat Hepatocytes ◽  
Adult Level ◽  
Enzyme Specific Activity ◽  
Cytochemical Reaction ◽  
And Control

The distribution of glucose-6-phosphatase activity in rat hepatocytes during a period of rapid endoplasmic reticulum differentiation (4 days before birth-1 day after birth) was studied by electron microscope cytochemistry. Techniques were devised to insure adequate morphological preservation, retain glucose-6-phosphatase activity, and control some other possible artifacts. At all stages examined the lead phosphate deposited by the cytochemical reaction is localized to the endoplasmic reticulum and the nuclear envelope. At 4 days before birth, when the enzyme specific activity is only a few per cent of the adult level, the lead deposit is present in only a few hepatocytes. In these cells a light deposit is seen throughout the entire rough-surfaced endoplasmic reticulum. At birth, when the specific activity of glucose-6-phosphatase is approximately equal to that of the adult, nearly all cells show a positive reaction for the enzyme and, again, the deposit is evenly distributed throughout the entire endoplasmic reticulum. By 24 hr postparturition all of the rough endoplasmic reticulum, and in addition the newly formed smooth endoplasmic reticulum, contains heavy lead deposits; enzyme activity at this stage is 250% of the adult level. These findings indicate that glucose-6-phosphatase develops simultaneously within all of the rough endoplasmic reticulum membranes of a given cell, although asynchronously in the hepatocyte population as a whole. In addition, the enzyme appears throughout the entire smooth endoplasmic reticulum as the membranes form during the first 24 hr after birth. The results suggest a lack of differentiation within the endoplasmic reticulum with respect to the distribution of glucose-6-phosphatase at the present level of resolution.

scholarly journals The use of proteinases to determine the topological location of cytochrome P-450 in vesicles derived from smooth endoplasmic reticulum of rat liver

1981 ◽  
Vol 196 (2) ◽  
pp. 585-589 ◽  
Author(s):  
M B Cooper ◽  
M R Estall ◽  
B R Rabin
Keyword(s):  
Lipid Peroxidation ◽  
Endoplasmic Reticulum ◽  
Membrane Proteins ◽  
Phosphatase Activity ◽  
Rat Liver ◽  
Smooth Endoplasmic Reticulum ◽  
Transverse Plane ◽  
Phospholipid Bilayer ◽  
Cytochrome P 450

1. The phospholipid bilayer of intact vesicles from smooth endoplasmic reticulum is impermeable to macromolecules. Specific and non-specific proteinases were used to investigate the site of membrane proteins in the transverse plane of the bilayer. 2. When two proteinases were used in conjunction, denaturing effects additional to proteolysis were observed on cytochrome P-450 content and glucose 6-phosphatase activity which did not depend on the integrity of the phospholipid bilayer. 3. When lipid peroxidation was inhibited, these effects were not observed.

Anisopachous Cisternae and Cubic Lattice Structures in Hepatocytes of Rats Treated with Aminotriazole

1974 ◽  
Vol 32 ◽  
pp. 200-201
Author(s):  
Z. Hruban ◽  
A. Slesers ◽  
M. Gotoh
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Young Male ◽  
Chow Diet ◽  
Sprague Dawley ◽  
Metabolizing Enzymes ◽  
Cubic Lattice ◽  
Sprague Dawley Rats ◽  
Tubular Endoplasmic Reticulum ◽  
Stimulation Of

Administration of 3-amino-l,2,4-triazole (AT) decreases the activities of drug-metabolizing enzymes and inhibits the stimulation of the drugmetabolizing activities by the administration of phenobarbital (1). In the present study 1% AT in chow diet was fed ad libitum to young male Sprague-Dawley rats for 6 weeks. Thyroxin was given at 0, 0.5, 1.0, 1.5 and 2.0 ng per liter of drinking water. It was established that 1.0 mg thyroxin/L is adequate to prevent thyromegaly induced by AT.Rats fed AT alone or with 0.5% acetylsalicylic acid for 6 weeks showed alterations of the endoplasmic reticulum in their liver cells. The hepatocytes contained variable amounts of conglomerates of the tubular smooth endoplasmic reticulum (Figs. 8, 9), some of which were less than 0.5 micron in diameter (Figs. 5, 6). The anastomosing tubules were more closely packed and the intertubular spaces were narrower when compared with tubular endoplasmic reticulum of normal hepatocytes.

Fine structure of the thraustochytrid Ulkenia amoeboidea. II. The amoeboid stage and formation of zoospores

1982 ◽  
Vol 60 (7) ◽  
pp. 1103-1114 ◽  
Author(s):  
S. Raghu Kumar
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Fine Structure ◽  
Nuclear Division ◽  
Smooth Endoplasmic Reticulum ◽  
Dense Granule ◽  
Multivesicular Bodies ◽  
Golgi Bodies ◽  
Dense Bodies ◽  
Spindle Microtubules

In the thraustochytrid Ulkenia amoeboidea (Bahnweg & Sparrow) Gaertner the contents of the mature vegetative thallus escape from the cell wall in the form of a limax cell. The limax cell is covered by a layer of scales and possesses a nucleus, a paranuclear body, Golgi bodies, mitochondria, bands of smooth endoplasmic reticulum, vacuoles, multivesicular bodies, and cisternae with filamentous contents. The posterior end is filled with smooth endoplasmic reticulum and fusiform vesicles. The anterior end is organelle free and filled with cytoplasm with free ribosomes. Subspherical dense bodies, bounded by a single membrane, are present. The limax cell rounds up prior to mitosis and the Golgi bodies increase in number. During mitosis, the nuclear membrane breaks down totally. Chromosomes are not well defined. Spindle microtubules arise from the centriole and enter the nucleus. After nuclear division, the nuclear envelope is reformed. Cytokinesis is by cleavage into two cells, accompanied by formation of microtubules along the cleavage furrows. The zoospore possesses a nucleus, a paranuclear body, mitochondria, vesicles with presumptive mastigonemes and kinetosome rootlet microtubules and they are covered by a layer of scales. An electron-dense granule and two peripheral thickenings are present within the lumen of the kinetosome.

scholarly journals FINE STRUCTURE OBSERVATIONS OF THE UPTAKE OF INTRAVENOUSLY INJECTED PEROXIDASE BY THE RAT CHOROID PLEXUS

1967 ◽  
Vol 15 (3) ◽  
pp. 160-165 ◽  
Author(s):  
NORWIN H. BECKER ◽  
ALEX B. NOVIKOFF ◽  
H. M. ZIMMERMAN
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Cerebrospinal Fluid ◽  
Choroid Plexus ◽  
Smooth Endoplasmic Reticulum ◽  
Multivesicular Bodies ◽  
Adult Rats ◽  
Dense Bodies ◽  
Pinocytotic Vesicles ◽  
Membrane Bound

The uptake by the choroid plexus of adult rats of intravenously injected horseradish peroxidase has been investigated by electron microscopy. Within 4 min, the injected protein passes the capillary and is rapidly distributed through extracellular space and choroidal cells. Peroxidase enters the choroidal cells within coated vesicles which act as pinocytotic vesicles. At 15 min, peroxidase activity is present in numerous membrane-bound vesicles, multivesicular bodies, dense bodies and what appear to be segments of smooth endoplasmic reticulum. None of the peroxidase-containing organelles is seen to empty to the ventricular surface. Egress of the extracellular peroxidase into the cerebrospinal fluid is apparently blocked by apical zonulae occludentes between the choroidal cells.

scholarly journals ELECTRON MICROSCOPIC LOCALIZATION OF GLYCOPROTEINS IN PITUITARY CELLS OF DUCK AND QUAIL

1971 ◽  
Vol 19 (12) ◽  
pp. 775-797 ◽  
Author(s):  
ANDRÉE TIXIER-VIDAL ◽  
RENÉE PICART
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Secretory Granules ◽  
Periodic Acid ◽  
Pituitary Cells ◽  
Electron Microscopic ◽  
Gonadotropic Cells ◽  
Dense Bodies

Structures demonstrating the presence of glycoproteins, acid phosphatase activity and OsO4 impregnation were localized by means of the electron microscope in duck and in quail pituitary cells. Two methods for the electron microscopic demonstration of glycoproteins were used: a chromic acid-phosphotungstic acid mixture on glycol-methacrylate-embedded tissues, and the periodic acid-thiocarbohydrazide-silver proteinate technique. Both methods showed glycoproteins in the following sites: ( a) the secretory granules in three types of cells (A, B, C) which are part of the seven different cells of the avian pituitary; ( b) the several kinds of dense bodies which are richer in reaction product than the secretory granules. A correlation with previous studies on similar species of birds is helpful in identifying each of the three positive types of cells as thyrotropic cell (A), prolactin cell (B) and gonadotropic cell (C). The presence of glycoproteins within the Golgi saccules (on condensing granules) was found with the periodic acid-thiocarbohydrazide-silver proteinate method in these gonadotropic cells only. In gonadotropic and thyrotropic cells, acid phosphatase activity is weak in the inner Golgi saccules and strong in the "Golgi Endoplasmic Reticulum Lysosomes" system, in the lysosomes, in the dense bodies and in the vacuolated dense bodies. The structures which are richest in glycoproteins are also those which have the most acid phosphatase activity. On the contrary, OsO4-stained structures in duck gonadotropic cells (nuclear pericisterna, rough endoplasmic reticulum, cisternae and outer Golgi saccules) have no glycoproteins or acid phosphatase activity.

scholarly journals Isolation of centrolobular and perilobular hepatocytes after phenobarbital treatment.

1975 ◽  
Vol 66 (1) ◽  
pp. 23-41 ◽  
Author(s):  
J C Wanson ◽  
P Drochmans ◽  
C May ◽  
W Penasse ◽  
A Popowski
Keyword(s):  
Endoplasmic Reticulum ◽  
Phosphatase Activity ◽  
Glycogen Phosphorylase ◽  
Smooth Endoplasmic Reticulum ◽  
Morphological Characteristics ◽  
Preceding Paper ◽  
Cell Populations ◽  
Liver Lobule ◽  
Mean Diameter ◽  
Glycogen Particles

Daily phenobarbital (PB) injections, on 3-7 consecutive days, induce an intense proliferation of smooth endoplasmic reticulum (ER) associated with a decrease of the glucose-6-phosphatase activity. This situation first affects the centrolobular hepatocytes, enhancing the degree of liver lobule heterogeneity. This experimental model was used for isolation and further subfractionation of hepatocytes on Ficoll density gradients, as described in the preceding paper. Profiles of protein, DNA, RNA, glycogen, phosphorylase, and glucose-6-phosphatase were determined all along the gradient. Two liver cell populations were distinguished: (a) light hepatocytes (mean density 1.10) present the same morphological characteristics as centrolobular cells, i.e., an abundant smooth ER composed of tubular elements, numerous small mitochondria, and few glycogen particles; (b) heavy hepatocytes (mean density 1.14) are characterized by large and compact glycogen areas and prominent rough endoplasmic cisternae, as are the perilobular cells. After incubation in the Wachstein-Meisel medium, Centrolobular hepatocytes exhibit dispersed reaction sites of glucose-6-phosphatase activity, whereas perilobular cells present a continuous and intense reaction. Morphometric determinations were carried out for both cell populations. Centrolobular PB hepatocytes are considerably enlarged (mean diameter: 23.7 mum); perilobular hepatocytes have a significantly smaller mean diameter of 19.2 mum, which is close to the values of control liver cells.

The Fine Structure Of Photoreceptors In Mitopus Morio (Phalangida)

1969 ◽  
Vol 4 (2) ◽  
pp. 327-351
Author(s):  
D. J. CURTIS
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membranes ◽  
Acetylcholinesterase Activity ◽  
Structural Studies ◽  
Hexagonal Array ◽  
Laminated Structure ◽  
Dense Bodies ◽  
Single Lens ◽  
Dioptric Apparatus ◽  
Stimulation Of

Fine structural studies on the eyes of the harvestman Mitopus morio revealed the presence of microvilli in the rhabdom. The microvilli vary in length between 1 µ and 2 µ, are about 800 Å wide, and curved or straight. They derive from the plasma membranes of the four retinula cells which surround the rhabdom. Approximately cylindrical in shape, the rhabdoms are about 40 µ long by about 4-6 µ in cross-diameter. Each rhabdom is situated at the centre of a retinula, and these retinulae are packed in a hexagonal array to form the retina. Distally, rhabdom fusion occurs to form a rhabdom network. The retina lies beneath the dioptric apparatus which consists of a single lens, surmounting a glassy body composed of lentigen cells. The cytoplasmic organelles of the retinula cells include mitochondria, lysosomes, sparse elements of endoplasmic reticulum, vesicular components, prominent Golgi complexes and pigment granules which possess a laminated structure. An important feature of the retinula cell is the presence of many small vesicles, about 0.1 µ in diameter, clustered beneath the rhabdom. Incubation of glutaraldehyde-fixed eyes in a Gomori medium with acetylthiocholine as substrate, coupled with inhibition of controls by 62C47, indicates the presence of a presumed acetylcholinesterase in these vesicles. Similar vesicles also occur in the proximal cytoplasm of the retinula cells. Other larger vesicles, often with a core of whorled membranes, as well as dense bodies, also show acetylthiocholine-splitting activity. This latter activity is not inhibited by 62C47 and is probably the effect of lysosomal non-specific esterase. These bodies also exhibit acid phosphatase activity when incubated in a Gomori medium with β-glycerophosphate as substrate. The presence of acetylcholinesterase activity, as distinct from non-specific esterase, in vesicles closely associated with the rhabdom and in more proximally situated vesicles is significant. It would point to the presence of an acetylcholine/acetylcholinesterase system involved in the generation and/or propagation of the sensory impulse arising from photo-stimulation of the rhabdom.

scholarly journals CYTOLOGICAL ALTERATIONS RELATED TO STIMULATION OF THE ZONA GLOMERULOSA OF THE ADRENAL GLAND

1965 ◽  
Vol 26 (2) ◽  
pp. 499-521 ◽  
Author(s):  
Filiberto Giacomelli ◽  
Joseph Wiener ◽  
David Spiro
Keyword(s):  
Endoplasmic Reticulum ◽  
Adrenal Gland ◽  
Light And Electron Microscopy ◽  
Zona Glomerulosa ◽  
High Electron ◽  
Dense Bodies ◽  
Large Numbers ◽  
Cytological Alterations ◽  
Parallel Arrays ◽  
Stimulation Of

The structure of the zona glomerulosa of the rat adrenal gland stimulated by sodium restriction has been studied by light and electron microscopy. The major changes observed during the course of the experiment in stimulated glands involve cytoplasmic droplets, mitochondria, and the endoplasmic reticulum. There is a progressive decrease in the number of cytoplasmic droplets of low electron opacity. Numerous, greatly elongated mitochondria containing parallel arrays of tubules are noted. These tubules extend from within the mitochondria through gaps in the mitochondrial-limiting membranes into the cytoplasm. In addition, amorphous intramitochondrial deposits, possibly aldosterone precursors, are seen. Increased amounts of smooth-surfaced endoplasmic reticulum, often showing complex arrangements, are another feature of the stimulated zona glomerulosa. Other alterations include the presence of large numbers of dense bodies as well as cytoplasmic droplets of high electron opacity. These observations are discussed in relation to the biosynthesis of aldosterone.

Sign in / Sign up

Export Citation Format

Share Document