Association of progesterone with a unique particulate fraction of the human corpus luteum

1988 ◽  
Vol 116 (2) ◽  
pp. 307-312 ◽  
Author(s):  
T. A. Bramley ◽  
G. S. Menzies
Keyword(s):  
Plasma Membrane ◽  
Corpus Luteum ◽  
Plasma Membranes ◽  
Buoyant Density ◽  
Particulate Fraction ◽  
Luteal Cell ◽  
Cell Plasma Membrane ◽  
Intracellular Organelle ◽  
Cell Plasma ◽  
Human Corpus Luteum

ABSTRACT Homogenates of human corpus luteum were fractionated on continuous sucrose density gradients, with and without pretreatment with digitonin to perturb plasma membranes. Fractions of each gradient were assayed for steroid content and a range of plasma membrane and intracellular organelle markers. Progesterone and oestradiol were associated with a particulate fraction (buoyant density, 1·08–1·13 g/cm3). The buoyant density distribution of these steroids was distinct from those of the luteal cell plasma membrane and intracellular organelle markers tested. Treatment with digitonin increased the buoyant density of both progesterone and oestradiol. If steroids are contained in distinct vesicles, these vesicles may be involved in the sequestration of newly synthesized steroid and its movement to the cell surface for release into the circulation. J. Endocr. (1988) 116, 307–312

Two Phases Of Ferricyanide Reductase Activity In Ehrlich Cell Plasma Membranes

1992 ◽  
Vol 47 (11-12) ◽  
pp. 929-931 ◽  
Author(s):  
Antonio del Castillo-Olivares ◽  
Javier Márquez ◽  
Ignacio Núñez de Castro ◽  
Miguel Angel Medina
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Reductase Activity ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Cell Plasma Membrane ◽  
Ferricyanide Reductase ◽  
Ehrlich Cell ◽  
Cell Plasma ◽  
Two Phases

Ehrlich cell plasma membrane vesicles have a ferricyanide reductase activity that shows two phases. These two phases were kinetically characterized. Evidence is presented for a differential effect of trypsin on both phases

Specific binding sites for progesterone in subcellular fractions of the porcine corpus luteum

1994 ◽  
Vol 142 (1) ◽  
pp. 101-110 ◽  
Author(s):  
G S Menzies ◽  
T A Bramley
Keyword(s):  
Corpus Luteum ◽  
Early Pregnancy ◽  
Binding Sites ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Buoyant Density ◽  
Subcellular Fractions ◽  
Particulate Fraction ◽  
Luteal Cell

Abstract Subcellular fractionation of porcine corpus luteum (CL) homogenates on continuous sucrose gradients has previously demonstrated that most of the endogenous progesterone of the CL was associated with a unique particulate fraction. Exogenous radiolabelled steroids were also sequestered with some specificity by this fraction. We now report that this particulate fraction is capable of binding high levels of exogenous 3H-labelled progesterone (and pregnenolone) in vitro, but only in the presence of the saponin, digitonin. Binding was dependent on the pH, temperature and duration of incubation, and showed specificity and high affinity for progesterone (Kd, 79 nm). Androgens, oestrogens and pregnenolone competed for porcine luteal [3H] progesterone binding sites, but only at much higher concentrations, whereas cholesterol, a number of progesterone receptor agonist and antagonist analogues and inhibitors of 3β-hydroxysteroid dehydrogenase and C17-hydroxylase/C17,20-lyase did not compete. Analysis of profiles for a number of luteal cell-surface membrane and intracellular organelle markers confirmed previous studies showing the association of an NADH-cytochrome C reductase with this fraction. Moreover, the content of endogenous progesterone associated with particulate subcellular fractions isolated from porcine granulosa cell (GC) and CL homogenates at different stages of the luteal phase and early pregnancy waxed and waned with the stage of the luteal phase (and the secretory activity of the CL). Binding of [3H]progesterone in vitro equilibrated at the same buoyant density as endogenous progesterone: levels of both were highest during the mid-luteal phase and during early pregnancy, lower in early and late luteal CL, and undetectable in corpora albicantia. In contrast, relaxin secretory granules were readily resolved from progesterone binding sites. We propose that these particulate progesterone binding sites may be involved in the sequestration and/or packaging of newly-synthesized steroid for secretion by the luteal cell, or may mediate actions of progesterone within the luteal cell. Journal of Endocrinology (1994) 142, 101–110

Subcellular fractionation of the porcine corpus luteum: sequestration of progesterone in a unique particulate fraction

1988 ◽  
Vol 117 (3) ◽  
pp. 341-354 ◽  
Author(s):  
T. A. Bramley ◽  
G. S. Menzies
Keyword(s):  
Cytochrome C ◽  
Cell Surface ◽  
Corpus Luteum ◽  
Reductase Activity ◽  
Buoyant Density ◽  
Particulate Fraction ◽  
Luteal Cell ◽  
Cytochrome C Reductase ◽  
Intracellular Organelles ◽  
Nadh Cytochrome

ABSTRACT Homogenates of porcine corpus luteum were subjected to fractionation by differential-rate centrifugation or sucrose density gradient fractionation, with or without pretreatment with digitonin. Fractions of each gradient were assayed for a number of markers characteristic of the major intracellular organelles and cell-surface membranes, and for progesterone content. The majority of the progesterone content of homogenates of porcine corpus luteum was associated with a low-density particulate fraction which equilibrated at a buoyant density of 1·07–1·09 g/cm3. Pretreatment with digitonin increased the buoyant density of the progesterone-enriched fraction markedly (to 1·13–1·15 g/cm3) without causing release of steroid. The density distributions of progesterone content in control and digitonin-treated luteal gradient fractions were quite distinct from those of the major intracellular organelles and luteal cell-surface membranes. However, NADH–cytochrome C reductase activity (but not other endoplasmic reticulum markers) was also enriched in this fraction. The results suggest that most of the progesterone of the porcine corpus luteum is associated with a unique particulate fraction which is enriched in digitonin-reactive lipids and NADH–cytochrome C reductase activity. J. Endocr. (1988) 117, 341–354

scholarly journals Influence of omega-3 fatty acids on bovine luteal cell plasma membrane dynamics

2017 ◽  
Vol 1859 (12) ◽  
pp. 2413-2419 ◽  
Author(s):  
Michele R. Plewes ◽  
Patrick D. Burns ◽  
Richard M. Hyslop ◽  
B. George Barisas
Keyword(s):  
Fatty Acids ◽  
Plasma Membrane ◽  
Membrane Dynamics ◽  
Luteal Cell ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Cell Plasma Membrane ◽  
Cell Plasma

Specificity studies of particulate binding sites for steroid hormones in subcellular fractions of the porcine corpus luteum

1993 ◽  
Vol 136 (3) ◽  
pp. 371-380 ◽  
Author(s):  
T. A. Bramley ◽  
G. S. Menzies
Keyword(s):  
Corpus Luteum ◽  
Binding Sites ◽  
Steroid Receptors ◽  
Buoyant Density ◽  
Particulate Fraction ◽  
Luteal Cell ◽  
Similar Extent ◽  
Oestrone Sulphate ◽  
Porcine Granulosa Cell ◽  
Lipophilic Substances

ABSTRACT We have studied the binding of a number of radiolabelled steroids and lipophilic substances to porcine corpus luteum (CL) particulate fractions. Following preincubation of CL homogenates with radiolabelled progesterone or pregnenolone prior to fractionation on continuous sucrose density gradients, a broad peak of binding was observed associated with a particulate fraction of buoyant density 1·05–1·10 g/cm3. Progesterone content also peaked at a similar buoyant density (1·06–1·12 g/cm3). Pretreatment of luteal homogenates with digitonin perturbed the buoyant density of the progesterone-binding particulate fraction to 1·10–1·14 g/cm3 and sharpened the binding peak. Progesterone content was also perturbed to a similar extent by digitonin pretreatment, without release of the steroid. Oestrogens were also sequestered by this fraction, but steroid precursors (cholesterol, cholesterol ester), corticosteroids (cortisol, corticosterone), sterol conjugates (oestrone sulphate, pregnanediol glucuronide) and other lipophilic substances (arachidonic acid, phospholipid, prostaglandins E1, E2 and F2α) were not bound. Androgens were bound weakly by fractions from control gradients but, in the presence of digitonin, significant binding could be demonstrated. Radiolabelled steroids were shown to interact directly with luteal membrane fractions, rather than interacting first with cytosolic steroid receptors which then bound to membranes. Furthermore, [3H]progesterone was not bound by porcine granulosa cell particulate fractions. These observations suggest that this fraction may be involved in sequestration or packaging of progesterone for secretion by the luteal cell. Journal of Endocrinology (1993) 136, 371–380

Stimulation of Tumor-Specific Immunity Using Tumor Cell Plasma Membrane Antigen

Methods ◽  
1997 ◽  
Vol 12 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Matthew F Mescher ◽  
Elena Savelieva
Keyword(s):  
Plasma Membrane ◽  
Tumor Cell ◽  
Cell Plasma Membrane ◽  
Specific Immunity ◽  
Cell Plasma ◽  
Stimulation Of

scholarly journals Charged anaesthetics alter LM-fibroblast plasma-membrane enzymes by selective fluidization of inner or outer membrane leaflets

1986 ◽  
Vol 239 (2) ◽  
pp. 301-310 ◽  
Author(s):  
W D Sweet ◽  
F Schroeder
Keyword(s):  
Plasma Membrane ◽  
Active Site ◽  
Plasma Membranes ◽  
Local Anaesthetics ◽  
Cationic Drugs ◽  
Cell Plasma ◽  
Composition And Structure ◽  
Highly Sensitive ◽  
Functional Consequences ◽  
Anionic Drugs

The functional consequences of the differences in lipid composition and structure between the two leaflets of the plasma membrane were investigated. Fluorescence of 1,6-diphenylhexa-1,3,5-triene(DPH), quenching, and differential polarized phase fluorimetry demonstrated selective fluidization by local anaesthetics of individual leaflets in isolated LM-cell plasma membranes. As measured by decreased limiting anisotropy of DPH fluorescence, cationic (prilocaine) and anionic (phenobarbital and pentobarbital) amphipaths preferentially fluidized the cytofacial and exofacial leaflets respectively. Unlike prilocaine, procaine, also a cation, fluidized both leaflets of these membranes equally. Pentobarbital stimulated 5′-nucleotidase between 0.1 and 5 mM and inhibited at higher concentrations, whereas phenobarbital only inhibited, at higher concentrations. Cationic drugs were ineffective. Two maxima of (Na+ + K+)-ATPase activation were obtained with both anionic drugs. Only one activation maximum was obtained with both cationic drugs. The maximum in activity below 1 mM for all four drugs clustered about a single limiting anisotropy value in the cytofacial leaflet, whereas there was no correlation between activity and limiting anisotropy in the exofacial leaflets. Therefore, although phenobarbital and pentobarbital below 1 mM fluidized the exofacial leaflet more than the cytofacial leaflet, the smaller fluidization in the cytofacial leaflet was functionally significant for (Na+ + K+)-ATPase. Mg2+-ATPase was stimulated at 1 mM-phenobarbital, unaffected by pentobarbital and slightly stimulated by both cationic drugs at concentrations fluidizing both leaflets. Thus the activity of (Na+ + K+)-ATPase was highly sensitive to selective fluidization of the leaflet containing its active site, whereas the other enzymes examined were little affected by fluidization of either leaflet.

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