Effect of cysteamine on the lysosomal enzymes of the hyperprolactinaemic rat pituitary

1990 ◽  
Vol 125 (1) ◽  
pp. 75-80 ◽  
Author(s):  
T. M. Jeitner ◽  
J. R. Oliver
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzyme ◽  
Protease Activity ◽  
Lysosomal Enzymes ◽  
Intact Cells ◽  
Enzyme Degradation ◽  
Rat Pituitary ◽  
Prolactin Content ◽  
Inhibited Acid

ABSTRACT The effect of cysteamine on the activity of lysosomal enzymes and the prolactin content of isolated hyperprolactinaemic cells has been investigated. In broken cell preparations, cysteamine markedly stimulated acid prolactin protease activity. In intact cells, however, cysteamine inhibited acid prolactin protease activity and β-galactosidase. Moreover, the activities of α-mannosidase, acid phosphatase, β-glucuronidase, total arylsulphatase and hexosaminidase were not changed by the addition of cysteamine. Cysteamine significantly depleted the cells of prolactin, and this action was not compromized by the inclusion of either leupeptin, chloroquine or NH4Cl in the incubation media. Taken together, these results indicate that cysteamine does not promote degradation of prolactin and hence depletion of prolactin from the pituitary through a mechanism involving lysosomal enzyme degradation. Journal of Endocrinology (1990) 125, 75–80

scholarly journals Relationship of prostaglandin secretion by rabbit alveolar macrophages to phagocytosis and lysosomal enzyme release

1979 ◽  
Vol 184 (2) ◽  
pp. 345-354 ◽  
Author(s):  
Wei Hsueh ◽  
Charles Kuhn ◽  
Philip Needleman
Keyword(s):  
Arachidonic Acid ◽  
Acid Phosphatase ◽  
Alveolar Macrophages ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Cytochalasin B ◽  
Neutral Lipids ◽  
Prostaglandin Synthesis ◽  
Enzyme Release ◽  
Control Value

The phospholipids of rabbit alveolar macrophages were pulse-labelled with [14C]-arachidonic acid, and the subsequent release of labelled prostaglandins was measured. Resting macrophages released measurable amounts of arachidonic acid, the prostaglandins E2, D2 and F2α and 6-oxoprostaglandin F1α. Phagocytosis of zymosan increased the release of arachidonic acid and prostaglandins to 2.5 times the control value. In contrast, phagocytosis of inert latex particles had no effect on prostaglandin release. Indomethacin inhibited the release of prostaglandin, and, at high doses (20μg/ml), increased arachidonic acid release. Analysis of the cellular lipids showed that after zymosan stimulation the proportion of label was decreased in phosphatidylcholine, but not in other phospholipids or neutral lipids. Cytochalasin B, at a dose of 2μg/ml, inhibited the phagocytosis induced by zymosan but increased prostaglandin synthesis to 3.4 times the control. These data suggest that the stimulation of prostaglandin synthesis by zymosan is not dependent on phagocytosis. Exposure to zymosan also resulted in the release of the lysosomal enzyme, acid phosphatase. Furthermore, cytochalasin B augmented the zymosan-stimulated release of acid phosphatase at the same dose that stimulated prostaglandin synthesis. However, indomethacin, at a dose that completely inhibited prostaglandin synthesis, failed to block the lysosomal enzyme release. Thus despite some parallels between the release of prostaglandins and lysosomal enzymes, endogenous prostaglandins do not appear to mediate the release of lysosomal enzymes. The prostaglandins released from the macrophages may function as humoral substances affecting other cells.

scholarly journals MODIFICATION OF ZYMOSAN-INDUCED RELEASE OF LYSOSOMAL ENZYMES FROM HUMAN POLYMORPHONUCLEAR LEUKOCYTES BY CYTOCHALASIN B

1974 ◽  
Vol 62 (3) ◽  
pp. 625-634 ◽  
Author(s):  
John L. Skosey ◽  
Evelyn Damgaard ◽  
Donald Chow ◽  
Leif B. Sorensen
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzyme ◽  
Incubation Medium ◽  
Polymorphonuclear Leukocytes ◽  
Lysosomal Enzymes ◽  
Cytochalasin B ◽  
Enhanced Recovery ◽  
Extracellular Enzyme ◽  
Enzyme Release ◽  
Extracellular Medium

During the process of phagocytosis, polymorphonuclear leukocytes (PMN) release lysosomal enzymes into the extracellular medium. When the antibiotic cytochalasin B (CB) is present in the incubation medium along with phagocytable particles, enhanced recovery of enzyme activities from the incubation medium has been observed. These findings have led to the interpretation that CB enhances lysosomal enzyme release. Our results contradict this interpretation. The lysosomal enzymes acid phosphatase and ß-galactosidase are unstable after they are released from cells. During the first 5–15 min of phagocytosis, significant amounts of both acid phosphatase and ß-galactosidase can be recovered from the extracellular medium. After this, the recovery of enzyme from the medium declines, presumably because the rate of loss of lysosomal enzyme activity exceeds the rate of release at later time periods. In the presence of CB, the appearance of lysosomal enzymes in the extracellular medium of cells exposed to zymosan is retarded for 5–10 min, after which it begins and then continues for approximately 20 min. At the end of a 30-min incubation period, therefore, in the absence of CB, extracellular levels of lysosomal enzymes (especially those which are unstable) are declining toward low levels while, in the presence of CB, extracellular enzyme levels are continuing to rise. We also measured the lysosomal enzyme remaining within cells after exposure to zymosan. CB retarded the disappearance of enzyme from cells and resulted in significantly less total cell enzyme loss. Thus, in the presence of CB, a greater proportion of the lysosomal enzyme lost from cells is recovered in the extracellular medium. In contrast to the previous conclusions that CB enhances lysosomal enzyme release, our results indicate that CB delays and decreases the zymosan-stimulated release of lysosomal enzymes from PMN. Since CB inhibits phagocytosis by PMN, our results indicate that the antibiotic modifies the mechanism of release of lysosomal enzymes, resulting in zymosan stimulation of their release independently of phagocytosis.

The Effect of Cortisone Acetate on Lysosomal Enzyme Levels In Rat Liver

1972 ◽  
Vol 50 (1) ◽  
pp. 20-24 ◽  
Author(s):  
A. Kyaw ◽  
A. Mellors
Keyword(s):  
Acid Phosphatase ◽  
Rat Liver ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Specific Activity ◽  
Cortisone Acetate ◽  
Maximum Increase ◽  
Tyrosine Transaminase ◽  
Specific Activities

Increases in the levels of four lysosomal enzymes were measured during the induction of tyrosine transaminase in rat liver by cortisone acetate. Tyrosine transaminase showed a maximum specific activity 2 h after the injection of the steroid hormone whereas lysosomal enzyme levels reached a maximum specific activity at 4 h. The maximum increase in specific activity for 15 injected animals compared to 15 controls was 100% for tyrosine transaminase; 40% for cathepsin A, cathepsin D, and β-N-acetylglucosaminidase; and 10% for acid phosphatase. Increased specific activities from livers of cortisone-acetate-treated rats were observed when lysosomal enzymes were released both by detergent treatment and by freezing and thawing.The increased specific activities were found in the readily solubilized lysosomal enzyme fractions and not in those lysosomal enzyme fractions which remain associated with particulate matter after lysosomal disruption. Similar increased specific activities for acid phosphatase and β-N-acetylglucosaminidase were observed in cultures of Morris hepatoma cells from rat liver when incubated with cortisone acetate in vitro. Thus the response appears to be typical of single cell types.

scholarly journals Phagolysosome formation in normal and colchicine-treated macrophages.

1975 ◽  
Vol 142 (4) ◽  
pp. 903-913 ◽  
Author(s):  
E L Pesanti ◽  
S G Axline
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzyme ◽  
Peritoneal Macrophages ◽  
Cell Type ◽  
Inert Particles ◽  
Time Periods ◽  
Mouse Peritoneal Macrophages ◽  
Over Time

Intracellular lysosomal fusion has been evaluated in cultivated mouse peritoneal macrophages by measurement of transfer of acid phosphatase to polyvinyltoluene (PVT)-containing phagolysosomes. Enzyme transfer was found to be directly and significantly related to the uptake of PVT and to be independent of time allowed for phagolysosome formation over time periods of 15 min to 18 h. In addition, the extent of transfer of lysosomal enzyme to phagolysosomes was unaffected by treatment of the cells with 10(-6) M colchicine, a dose which eradicates morphologically identifiable microtubules in this cell type within 2 h. The data indicate that intracellular fusion of lysosomes with phagosomes in the macrophage does not require formed microtubules and suggest that fusion occurs promptly after interiorization of inert particles.

scholarly journals Lymphocyte Lysosomes and Lysosomal Enzymes in Chronic Lymphocytic Leukemia

Blood ◽  
1973 ◽  
Vol 41 (4) ◽  
pp. 511-518 ◽  
Author(s):  
Steven D. Douglas ◽  
Georg Cohnen ◽  
Erika KÖnig ◽  
GÜnter Brittinger
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzymes ◽  
Microscopic Level ◽  
Lymphocytic Leukemia ◽  
Electron Microscopic Level ◽  
Acid Hydrolase ◽  
Electron Microscopic ◽  
Normal Cells ◽  
Biochemical Studies ◽  
Cell Profile

Abstract Electron microscopic cytochemical and biochemical studies of lysosomal markers have been performed in unstimulated normal and chronic lymphotic leukemia (CLL) lymphocytes. Decreased activities of the lysosomal enzymes acid phosphatase and β-glucuronidase but not of the nonlysosomal enzyme malate dehydrogenase were observed in CLL lymphocytes as compared to normal cells. At the electron microscopic level, the number of membrane-bounded acid phosphatase-positive organelles was diminished in CLL cells. (Average 1.07 per cell profile in normal cells and 0.17 in CLL lymphocytes). The findings indicate that the diminution of acid hydrolase activities in CLL lymphocytes is most likely due to a reduced number of lysosomes, rather than to a diminished enzyme content of these organelles.

scholarly journals Secretion of β-N-acetylglucosaminidase isoenzymes by normal human fibroblasts

1978 ◽  
Vol 173 (2) ◽  
pp. 433-439 ◽  
Author(s):  
P Willcox
Keyword(s):  
Lysosomal Enzyme ◽  
Human Fibroblast ◽  
Lysosomal Enzymes ◽  
Culture Medium ◽  
Human Fibroblasts ◽  
The Other ◽  
Normal Human Fibroblast ◽  
Acid Hydrolases ◽  
Human Fibroblast Cultures ◽  
Normal Human

1. Secretion of the lysosomal enzyme beta-N-acetylglucosaminidase (EC 3.2.1.30) by normal human fibroblast cultures was linear with respect to time up to 96h. 2. Two forms of the A isoenzyme of beta-N-acetylglucosaminidase were found in the culture medium. One form was similar to the isoenzyme found in other extracellular fluids, such as plasma and tears, the other resembled the intracellular (lysosomal) enzyme. The presence of the two isoenzymes in the culture medium appears to reflect two distinct secretory processes. 3. It is suggested that plasma acid hydrolases may be destined for incorporation into lysosomes in a manner analogous to that described for the packaging of lysosomal enzymes by fibroblasts.

Trypanosoma brucei: Ecto-Phosphatase Activity Present on the Surface of Intact Procyclic Forms

1997 ◽  
Vol 52 (5-6) ◽  
pp. 351-358 ◽  
Author(s):  
Eloise C. Fernandes ◽  
José R. Meyer-Fernandes ◽  
Mário A. C. Silva-Neto ◽  
Anibal E. Vercesi
Keyword(s):  
Acid Phosphatase ◽  
Cell Surface ◽  
Cell Viability ◽  
Phosphatase Activity ◽  
Trypanosoma Brucei ◽  
Intact Cells ◽  
Vanadate Inhibition ◽  
Rate Of Hydrolysis ◽  
Ph Range

Abstract The results presented in this paper indicate that procyclic forms of Trypanosoma brucei possess a phosphatase activity detected in the external cell surface able to hydrolyze about 0.7 nmol ∙ mg−1. min−1 p-nitrophenylphosphate. A faster rate of hydrolysis was observed when membrane-enriched fractions were used. This activity is weakly sensitive to 1 mᴍ NaF, 10 mᴍ tartrate and 10 mᴍ levamizole but strongly inhibited by 0.1 mᴍ vanadate. Inhibition by both NaF and vanadate have a competitive character. This phosphatase activity decreases by increasing the pH from 6.8 to 8.4, a pH range in which cell viability was maintained during at least 1 hour. In the membrane-enriched fractions this phosphatase activity showed to be an acid phosphatase. In addition, intact cells could catalyze the dephosphorylation of [32P]phosphocasein phosphorylated at serine and threonine residues.

Microtubule modulation of biliary excretion of endogenous and exogenous hepatic lysosomal constituents

1984 ◽  
Vol 246 (1) ◽  
pp. G8-G15 ◽  
Author(s):  
R. B. Sewell ◽  
S. S. Barham ◽  
A. R. Zinsmeister ◽  
N. F. LaRusso
Keyword(s):  
Lysosomal Enzyme ◽  
Biliary Excretion ◽  
Lysosomal Enzymes ◽  
Male Rats ◽  
Enzyme Secretion ◽  
Initial Increase ◽  
Acute Administration ◽  
Subsequent Decrease ◽  
Before And After

We tested the hypothesis that hepatocyte microtubules modulate the biliary excretion of endogenous and exogenous constituents of hepatocyte lysosomes. We collected bile via bile fistulas from male rats before and after acute administration of colchicine and vinblastine, agents known to bind to hepatocyte microtubules; rats were then killed and livers were homogenized for biochemical analyses or processed for electron microscopy. Colchicine caused biphasic, parallel alterations in the biliary excretion of three lysosomal enzymes compared with control rats given saline or lumicolchicine; a peak rise in enzyme outputs of approximately 175% at 45-60 min after colchicine administration was followed by a sustained fall to approximately 25% of control values, which persisted for 2-4 h. When hepatocyte lysosomes were prelabeled in vivo by administration of [3H]Triton WR-1339, a nonionic detergent that is sequestered in hepatic lysosomes, the biliary excretion of radiolabel in response to colchicine paralleled the biliary excretion of the three lysosomal enzymes. Vinblastine also induced a biphasic response in biliary lysosomal enzyme output that was similar to that produced by colchicine administration. Morphometric analysis of electron micrographs of rat livers demonstrated changes in the number of lysosomelike vesicles in the vicinity of bile canaliculi after colchicine and vinblastine administration; the initial increase in lysosomal enzyme secretion was associated with a significant decrease in the number of pericanalicular lysosomes after both agents, while the subsequent decrease in enzyme secretion coincided with an increase in the number of pericanalicular lysosomes after vinblastine.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of kidney lysosomal acid phosphatase during compensatory renal hyperplasia in rats

1968 ◽  
Vol 46 (3) ◽  
pp. 499-502 ◽  
Author(s):  
B. M. Hegdekar
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzymes ◽  
Soluble Fraction ◽  
Female Rats ◽  
Enzyme Release ◽  
Lysosomal Fraction ◽  
Probable Role ◽  
Long Evans ◽  
Free Activity

Female rats of the Long-Evans hooded strain, 4–6 months old and weighing 275–300 grams, were subjected to unilateral nephrectomy and the acid phosphatase activity in the remaining kidney was studied at the end of 24, 48, 72 hours, and 8 days respectively. Most of the acid phosphatase was found in the particulate fraction in normal kidneys. The enzyme activity in the soluble fraction was found to have increased the second day after the operation, but decreased to the original level by the end of 72 hours. The free activity of the lysosomal fraction also increased by the end of second postoperative day. A change in the permeability of the lysosomal membrane before the enzyme release was observed. The probable role of lysosomal enzymes in the initiation of mitotic divisions during compensatory renal hyperplasia is discussed.

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