scholarly journals Effect of dual agonists on phosphoinositide pools in WRK-1 cells

1990 ◽  
Vol 269 (3) ◽  
pp. 633-637 ◽  
Author(s):  
M E Monaco ◽  
M Attinasi ◽  
K Koréh
Keyword(s):  
Time Course ◽  
Inositol Phosphates ◽  
Subsequent Treatment ◽  
Tumour Cells ◽  
The Other ◽  
Mammary Tumour ◽  
Lipid Pool ◽  
Phosphoinositide Cycle ◽  
Heterologous Desensitization ◽  
Hormone Sensitive

Both vasopressin and bradykinin activate the phosphoinositide cycle in WRK-1 rat mammary tumour cells. When the two agonists are added simultaneously, partial additivity is observed with respect to disappearance of prelabelled phosphoinositides and accumulation of inositol phosphates; no additivity is observed with respect to resynthesis of phosphatidylinositol as assessed by monitoring [32P]Pi incorporation. Lack of complete additivity can be explained, at least in part, by heterologous desensitization. In order to determine whether the two agonists were accessing a common or individual hormone-sensitive phosphoinositide pools, cells were incubated with [32P]Pi in the presence of either vasopressin or bradykinin and subsequently restimulated with the alternative agonist. The lipid pool labelled in the presence of either agonist was sensitive to subsequent treatment by the other ligand, suggesting a common phosphoinositide pool. However, when cells were incubated with [32P]Pi in the absence of agonists, the time course of labelling of the hormone-sensitive pool was different for bradykinin and vasopressin, with that for bradykinin becoming labelled within a much shorter time. Thus although there is a significant overlap between the phosphoinositide pools responding to vasopressin and bradykinin, there is a small fraction of the hormone-sensitive lipid which responds only to bradykinin.

scholarly journals Phorbol ester inhibition of the hormone-stimulated phosphoinositide cycle in WRK-1 cells

1986 ◽  
Vol 236 (1) ◽  
pp. 171-175 ◽  
Author(s):  
M E Monaco ◽  
R A Mufson
Keyword(s):  
Binding Affinity ◽  
Phorbol Ester ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Tumour Cells ◽  
Mammary Tumour ◽  
Phosphate Accumulation ◽  
Phosphoinositide Cycle ◽  
Inositol Phosphate Accumulation

WRK-1 rat mammary tumour cells respond to vasopressin with increased accumulation of inositol phosphates as well as increased precursor incorporation into phosphatidylinositol. The phorbol ester, phorbol 13-myristate 12-acetate (PMA) inhibits by 80% both inositol phosphate accumulation and increased precursor incorporation. This inhibition is much less evident at early times (2 min) than at later times (25 min). The vasopressin-induced rise in cytosolic free Ca2+ is inhibited in a similar manner. Oleoylacetylglycerol is inactive with respect to inhibition of vasopressin-induced increases in incorporation of 32P into phosphoinositides. PMA has no effect on vasopressin binding at saturating concentrations of the hormone and does not affect the binding affinity.

A search for a hormone-sensitive inositol lipid pool in WRK 1 mammary tumour cells

1989 ◽  
Vol 17 (1) ◽  
pp. 88-89 ◽  
Author(s):  
SARAH H. MACCALLUM ◽  
PHILIP A. HUNT ◽  
ROBERT H. MICHELL ◽  
CHRISTOPHER J. KIRK
Keyword(s):  
Tumour Cells ◽  
Mammary Tumour ◽  
Lipid Pool ◽  
Hormone Sensitive

The use of cells doubly labelled with [14C]inositol and [3H]inositol to search for a hormone-sensitive inositol lipid pool with atypically rapid metabolic turnover

1989 ◽  
Vol 122 (1) ◽  
pp. 379-389 ◽  
Author(s):  
S. H. Maccallum ◽  
C. J. Barker ◽  
P. A. Hunt ◽  
N. S. Wong ◽  
C. J. Kirk ◽  
...  
Keyword(s):  
Cell Lines ◽  
Inositol Phosphates ◽  
Phosphatidyl Inositol ◽  
Receptor Activation ◽  
Inositol Monophosphatase ◽  
Lipid Pool ◽  
Inositol Lipids ◽  
Prostaglandin F ◽  
Hormone Sensitive ◽  
Stimulation Of

ABSTRACT Some, though not all, previous studies have suggested that the inositol lipid which is hydrolysed during transmembrane signalling in response to receptor activation might be drawn from a metabolically discrete and relatively small hormone-sensitive lipid pool that turns over more rapidly than the bulk of membrane inositol lipid. In order to seek evidence for the existence of this putative hormone-sensitive lipid pool, we have double-labelled cells by growing them for 3 days in a medium containing [14C]inositol and then supplying them with [3H]inositol for the final 2 h before stimulation. We anticipated that stimulation of these doubly labelled cells might provoke the formation, from the postulated hormone-sensitive pool, of small quantities of relatively 3H-enriched inositol phosphates, and that these could be harvested from cells (provided that the cytosolic inositol monophosphatase and inositol 1,4-bisphosphate/inositol 1,3,4-trisphosphate 1-phosphatase activities are first inhibited by Li+). Experiments of this type, using both vasopressin-stimulated WRK1 rat mammary tumour cells and 3T3 mouse fibroblasts stimulated by prostaglandin F2α, have largely failed to demonstrate the formation of relatively 3H-enriched inositol phosphates. There was a tendency for phosphatidyl-inositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate to have slightly higher 3H: 14C ratios than phosphatidylinositol, but the 3H: 14C ratios of the inositol phosphates formed in stimulated cells were not substantially greater than the 3H: 14C ratios of the inositol lipids. We therefore conclude, at least for the two cell lines that we studied, that hormone-stimulated inositol lipid hydrolysis can call, either directly or indirectly, upon the majority of the inositol lipid complement of the stimulated cell. Journal of Endocrinology (1989) 122, 379–389

scholarly journals The inositol phosphates in WRK1 rat mammary tumour cells

1992 ◽  
Vol 286 (2) ◽  
pp. 459-468 ◽  
Author(s):  
N S Wong ◽  
C J Barker ◽  
A J Morris ◽  
A Craxton ◽  
C J Kirk ◽  
...  
Keyword(s):  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Inositol Trisphosphate ◽  
Periodate Oxidation ◽  
Tumour Cells ◽  
Mammary Tumour ◽  
Inositol Polyphosphate ◽  
Inositol Hexakisphosphate ◽  
Site Specific

1. A detailed structural survey has been made of the inositol phosphates of unstimulated and vasopressin-stimulated WRK-1 rat mammary tumour cells. Inositol phosphate peaks were separated by h.p.l.c., and structural assignments were made for more than 20 compounds by combinations of: (a) co-chromatography with labelled standards; (b) site-specific enzymic dephosphorylation; (c) complete and partial periodate oxidation, followed by h.p.l.c. of polyols and their stereospecific oxidation by dehydrogenases; and (d) ammoniacal hydrolysis. 2. The ‘inositol monophosphates’ fraction from unstimulated cells included an uncharacterized peak, probably containing some glycerophosphoinositol, and Ins(1:2-cyclic)P. Stimulation provoked accumulation of both Ins1P and Ins3P, of Ins2P, and of Ins5P and/or the enantiomers Ins4P and Ins6P. The proportions of Ins1P and Ins3P were determined by partial periodate oxidation and enantiomeric identification of the resulting glucitols. 3. Three inositol bisphosphate peaks were detected in unstimulated cells: Ins(1,4)P2 [this was distinguished chemically from its enantiomer Ins(3,6)P2], Ins(3,4)P2 and/or Ins(1,6)P2, and Ins(4,5)P2 and/or Ins(5,6)P2. On stimulation, Ins(1,4)P2 and Ins(3,4)P2 [and/or Ins(1,6)P2] levels increased, and Ins(1:2-cyclic,4)P2 and Ins(1,3)P2 were also formed. 4. Three inositol trisphosphate peaks were obtained from unstimulated cells: all increased during stimulation. These were Ins(1,3,4)P3 [with some Ins(1:2-cyclic,4,5)P3], Ins(1,4,5)P3 and Ins(3,4,5)P3 [and/or Ins(1,5,6)P3]. During stimulation, another compound, probably Ins(1,4,6)P3, appeared in the ‘Ins(1,4,5)P3 peak’. The ‘Ins(3,4,5)P3 peak’ contained a second trisphosphate, probably Ins(2,4,5)P3. 5. Three inositol tetrakisphosphates, namely Ins(1,3,4,6)P4, Ins(1,3,4,5)P4, were present in unstimulated cells, and all accumulated during stimulation. 6. Ins(1,3,4,5,6)P5, which is the most abundant inositol polyphosphate in these cells, a less abundant inositol pentakisphosphate and inositol hexakisphosphate were all unresponsive to stimulation.

scholarly journals Organization of the phosphoinositide cycle. Assessment of inositol transferase activity in purified plasma membranes

1993 ◽  
Vol 290 (1) ◽  
pp. 179-183 ◽  
Author(s):  
O M Santiago ◽  
L I Rosenberg ◽  
M E Monaco
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Density Gradient ◽  
Plasma Membranes ◽  
Sucrose Density Gradient ◽  
Tumour Cells ◽  
Assay System ◽  
Mammary Tumour ◽  
Transferase Activity ◽  
Phosphoinositide Cycle

Experiments were carried out to determine whether or not CDP-diacylglycerol:myo-inositol 3-phosphatidyltransferase (IT) activity (EC 2.7.8.11) could be detected in purified plasma-membrane fractions from WRK-1 rat mammary tumour cells. These cells have previously been shown to have a very active phosphoinositide cycle. Sucrose-density-gradient-purified plasma membranes contained no IT activity that could not be accounted for by endoplasmic-reticulum contamination. However, we also determined that the relative amount of IT activity in endoplasmic reticulum and plasma-membrane fractions could be altered by changing the concentration of detergent in the assay system.

EXPRESSION OF SOME IMMUNOLOGIC MARKERS FOR THE DIAGNOSIS OF SUSPECTED LYMPHOID LESIONS OF LYMPHOMA

2018 ◽  
Vol 8 (4) ◽  
pp. 28-33
Author(s):  
Mao Nguyen Van ◽  
Thao Le Thi Thu
Keyword(s):  
Correct Diagnosis ◽  
Tumour Cells ◽  
The Body ◽  
The Other ◽  
Cervical Region ◽  
Cross Sectional ◽  
Immunologic Markers ◽  
Microscopic Features ◽  
Poor Differentiation ◽  
Benign Tumours

Background: In practice it was difficult or impossible to have a correct diagnosis for the lymphoid proliferation lesions based on only H.E standard histopathology. In addition to histopathology, the application of immunohistochemistry was indispensable for the definitive diagnosis of the malignant or benign tumours and the origin of the tumour cells as well. Objectives: 1. To describe the gross and microscopic features of the suspected lesions of lymphoma; 2. To asses the expression of some immunologic markers for the diagnosis and classification of the suspected lesions of lymphoma. Materials and Method: Cross-sectional research on 81 patients diagnosed by histopathology as lymphomas or suspected lesions of lymphoma, following with immunohistopathology staining of 6 main markers including LCA, CD3, CD20, Bcl2, CD30 and AE1/3. Results: The most site was lymph node 58.1% which appeared at cervical region 72.3%, then the stomach 14.9% and small intestine 12.4%. The other sites in the body were met with lower frequency. Histopathologically, the most type of the lesions was atypical hyperplasia of the lymphoid tissue suspecting the lymphomas 49.4%, lymphomas 34.5%, the other diagnoses were lower including inflammation, poor differentiation carcinoam not excluding the lymphomas, lymphomas differentiating with poor differentiation carcinomas. Immunohistochemistry showed that, LCA, CD3, CD20, Bcl2, CD30 and AE1/3 were all positive depending on such type of tumours. The real lymphomas were 48/81 cases (59.3%), benign ones 35.8% and poor differentiated carcinomas 4.9%. Conclusion: Immunohistochemistry with 6 markers could help to diagnose correctly as benign or malignant lesions, classify and determine the origin of the tumour cells as lymphocytes or epithelial cells diagnosed by histopathology as lymphomas or suspected lesions of lymphomas. Key words: histopathology, immunohistochemistry, lymphomas, poor differentiated carcinomas, hyperplasia, atypicality

Recovery of subjective visual horizontal after unilateral vestibular deafferentation by intratympanic instillation of gentamicin

2006 ◽  
Vol 16 (1-2) ◽  
pp. 69-73 ◽  
Author(s):  
Yoshinari Takai ◽  
Toshihisa Murofushi ◽  
Munetaka Ushio ◽  
Shinichi Iwasaki
Keyword(s):  
Healthy Subjects ◽  
Time Course ◽  
Early Stage ◽  
Ccd Camera ◽  
The Other ◽  
Spontaneous Nystagmus ◽  
Vestibular Evoked Myogenic Potentials ◽  
Normal Range ◽  
Intratympanic Gentamicin ◽  
Unilateral Vestibular Deafferentation

The time course of the recovery of subjective visual horizontal (SVH) after unilateral vestibular deafferentation by intratympanic instillation of gentamicin was studied. Six patients who underwent intratympanic gentamicin instillation therapy for Meniere's disease (1 man and 5 women, 32 to 69 years of age) were enrolled in this study. For comparison, SVH in 23 healthy subjects (12 men and 11 woman, 23 to 48 years of age) was also measured. The mean ± SD of SVH in healthy subjects was 0.0 ± 1.1 deg. All of the 6 patients showed significantly deviated SVH toward the injected side-down at the early stage after the therapy. Although one patient showed recovery of SVH to the normal range 25 days after the injection, the other patients required more time for recovery. Three patients did not show recovery to the normal range after 1 year. On the other hand, spontaneous nystagmus observed using an infrared CCD camera in total dark disappeared after 35 days (median). Patients who had normal vestibular evoked myogenic potentials before the therapy showed a tendency of delay of recovery of SVH. The reasons why the recovery of SVH took longer than the disappearance of spontaneous nystagmus are discussed in this report.

scholarly journals The ionic basis of the hypo-osmotic depolarization in neurons from the opisthobranch mollusc Elysia chlorotica

1992 ◽  
Vol 163 (1) ◽  
pp. 169-186
Author(s):  
R. H. Quinn ◽  
S. K. Pierce
Keyword(s):  
Cell Volume ◽  
Time Course ◽  
The Other ◽  
Resting Potential ◽  
Ion Concentrations ◽  
Elysia Chlorotica ◽  
Apparent Relationship ◽  
Volume Recovery ◽  
Original Potential ◽  
Ionic Basis

The resting potential of identified cells (Parker cells) in the abdominal ganglion of Elysia chlorotica (Gould) depolarizes by about 30 mV in response to a 50% reduction in osmolality and returns to the original potential in 20 min. Cell volume recovery requires approximately 2 h. Thus, recovery of the resting potential is not dependent on recovery of cell volume. The hypo-osmotic depolarization persists following inhibition of the electrogenic Na+/K(+)-ATPase with ouabain, and the levels of extracellular K+ and Cl- have little effect on the magnitude of the depolarization, while decreasing extracellular Na+ concentration produces a depolarization of only 10 mV. This suggests that the hypo-osmotic depolarization in Parker cells results mostly from increased relative permeability to Na+. Following transfer from 920 to 460 mosmol kg-1, Na+, Cl- and proline betaine leave the cells while intracellular K+ is conserved. Loss of intracellular Na+ and conservation of intracellular K+ are dependent on active transport by the Na+/K(+)-ATPase. Na+ and proline betaine leave the cells with a time course that is much longer than that of the hypo-osmotic depolarization. Unlike the other solutes, most of the reduction in intracellular Cl- concentration occurs coincidentally with the hypo-osmotic depolarization. However, unlike the hypo-osmotic depolarization, bulk loss of Cl- does not require the reduction in osmolality, only the reduction in extracellular ion concentrations. There is no apparent relationship between membrane depolarization and the regulation of intracellular osmolytes in Elysia neurons following hypo-osmotic stress.

Vitamin D-induction of secretory responses in rat pituitary tumour (GH4C1) cells

1988 ◽  
Vol 117 (2) ◽  
pp. 293-298 ◽  
Author(s):  
J. D. Wark ◽  
V. Gurtler
Keyword(s):  
Vitamin D ◽  
Time Course ◽  
Cell Model ◽  
Hormone Secretion ◽  
Pituitary Tumour ◽  
Prolactin Secretion ◽  
Tumour Cells ◽  
Bay K 8644 ◽  
Similar Time ◽  
Rat Pituitary

ABSTRACT 1,25-Dihydroxyvitamin D3(1,25-(OH)2D3) selectively enhances prolactin gene expression in GH4C1 clonal rat pituitary tumour cells. Because this effect requires extracellular Ca2+, we studied the effect of 1,25-(OH)2D3 on another Ca2+-dependent process, agonist-induced hormone secretion. Pretreatment with 1,25-(OH)2D3 (1 nmol/l) caused at least 25-fold sensitization of GH4C1 cells to the voltage-sensitive Ca2+ channel agonist BAY K 8644 (methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5-carboxylate) as a prolactin secretagogue. This inductive effect of 1,25-(OH)2D3 followed a similar time-course to the enhancement of prolactin production. 1,25-(OH)2D3 had no effect on basal or BAY K 8644-induced 45Ca2+ uptake. The Ca2+-selective divalent cation ionophore 11,19,21-trihydroxy-4,6,8,12,14,18,20-heptamethyl-9-oxo-22-(tetrahydro-5 methyl-5-tetra hydro-5-(1-hydroxyethyl)-5-methyl-2-furanyl)-10,16-docosadienoic acid (ionomycin; 12 nmol/l–1·2 μmol/l) caused no significant increase in prolactin secretion in the absence of 1,25-(OH)2D3, but in cells treated with 1,25-(OH)2D3-(1 nmol/l), it increased prolactin secretion by 73% at 12 nmol/l and by a maximum of 98% at 0·12 μmol/l. These data demonstrate that vitamin D markedly enhances the responsiveness of GH4C1 functional pituitary tumour cells to two secretagogues which acts primarily through Ca2+-dependent mechanisms. They support the proposal that 1,25-(OH)2D3 acts in this cultured cell model either by effecting a redistribution of intracellular Ca2+ or by increasing the response of a Ca2+ -sensitive effector system, but not by enhancing agonist-induced Ca2+ uptake. J. Endocr. (1988) 117, 293–298

An Electromyographic Analysis of Forelimb Muscles during Overground Stepping in the Cat

1978 ◽  
Vol 76 (1) ◽  
pp. 105-122 ◽  
Author(s):  
ARTHUR W.M. ENGLISH
Keyword(s):  
Energy Absorption ◽  
Time Course ◽  
The Other ◽  
Biphasic Pattern ◽  
The Third ◽  
Shoulder Region ◽  
Forelimb Muscles ◽  
Electromyographic Analysis ◽  
Adult Cats ◽  
Intramuscular Electromyography

The patterns of activity of 33 forelimb muscles during unrestrained overground stepping in eight adult cats were analysed using intramuscular electromyography. Three general patterns were found. Some muscles began activity during the first extension epoch (E1) and ceased near the end of the third extension epoch (E3) and were considered extensors. Others, considered flexors, began activity just prior to the flexion (F) epoch and ceased at or just after the onset of E1. Other muscles showed a biphasic pattern of activation; one period of activity occurring during F, the other during the extension epochs. In all regions of the limb, individual muscles displayed variation in the onset and time course of activity. The results are interpreted in terms of a model of locomotor generation which proposes specific neural output to individual muscles. Muscles of the shoulder region are proposed to act mainly to produce translatory and rotatory movements of the scapula associated with lengthening the step. Muscles of the elbow region and antebrachium are interpreted as playing roles both in producing flexionextension movements and in the absorption of energy. The latter group are considered especially suitable to energy absorption because of their pennate arrangement of muscle fasciculi and their long tendons.

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