Effect of Steroids and ‘Triton X-100’ on Glucose-Filled Phospholipid/cholesterol Structures

Weissmann, Gerald; Sessa, Grazia; Weissmann, Siegmund

doi:10.1038/208649a0

Cited by 41 publications

(16 citation statements)

References 15 publications

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“…Liposomes and hormones or other test compounds have generally been incubated within dialysis bags (3,21) but, in this work (with the exception of the experiment illustrated in Fig. 7 …”

Section: Methodsmentioning

confidence: 99%

“…One of the simplest manifestations of steroid action is the alteration of permeability of synthetic model membrane systems (3,9,21). The models are based on the fact that phospholipids, one of the major components of natural membranes, when dispersed in aqueous media, produce self-ordered particles which display many of the properties of natural membranes (6).…”

Section: Introductionmentioning

confidence: 99%

“…One-ml samples of the separated micelles were then combined with the hormone or other compound under test and incubated, under N2, for 1 hr at 35 C. When gibberellic acid was used, the desired amount of hormone was deposited directly into the test tube from a 5 mm methanolic stock solution. The methanol was removed by a stream of N2 before the addition of the micelles.Liposomes and hormones or other test compounds have generally been incubated within dialysis bags (3,21) but, in this work (with the exception of the experiment illustrated in Fig. 7 …”

mentioning

confidence: 99%

“…These two classes of compounds, steroids and gibberellins, also share the properties of isoprenoid structure (and, thus, a common biosynthetic pathway), similarity in structural diversity (through insertion or deletion of double bonds, radicals, subsidiary ring structures), and control of comparable physiological functions. It would seem possible that gibberellins and steroids also share at least one common trigger or hormonal mechanism.One of the simplest manifestations of steroid action is the alteration of permeability of synthetic model membrane systems (3,9,21). The models are based on the fact that phospholipids, one of the major components of natural membranes, when dispersed in aqueous media, produce self-ordered particles which display many of the properties of natural membranes (6).…”

mentioning

confidence: 99%

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The Influence of Gibberellic Acid on the Permeability of Model Membrane Systems

Wood

Paleg

1972

Plant Physiol.

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Gibberellic acid increases the permeability of model membranes composed of various plant-source lipids, a sterol, and dicetyl phosphate. As a result of hormone treatment, the flux of uncharged molecules such as glucose or sucrose, or charged ions such as chromate, through the model membranes (liposomes or micelies) is increased. The revelance of this finding to the in vivo effects of the hormone is briefly discussed.Plant hormones are both fewer in number and less variable in structure and function than their animal counterparts. In only one case, the gibberellins, do plant hormones approach the diversity apparent with animal steroids. These two classes of compounds, steroids and gibberellins, also share the properties of isoprenoid structure (and, thus, a common biosynthetic pathway), similarity in structural diversity (through insertion or deletion of double bonds, radicals, subsidiary ring structures), and control of comparable physiological functions. It would seem possible that gibberellins and steroids also share at least one common trigger or hormonal mechanism.One of the simplest manifestations of steroid action is the alteration of permeability of synthetic model membrane systems (3,9,21). The models are based on the fact that phospholipids, one of the major components of natural membranes, when dispersed in aqueous media, produce self-ordered particles which display many of the properties of natural membranes (6). The physiological pertinence of the models was enhanced by the finding that they demonstrated comparable responses to compounds which affect membranes in vivo (3). The permeability of the model structures (micelles or liposomes) is influenced by detergents, some antibiotics, and toxins, which increase permeability, and anti-inflammatory drugs and anaesthetics, which decrease permeability (16). Sterols may either increase or decrease permeability of the liposomes, and in one study, there was a high degree of correlation between the release of acid phosphatase from lysosomes and the increase in permeability of liposomes, with a range of sterols (3). Some sterols which decrease permeability of the model system have also been shown to act in a similar way in higher plant tissue, i.e., they protect red beet tissue from alcohol-induced damage in vivo (8). In addition, the in vivo effect of the polyene antibiotic, filipin, in increasing permeability of pea stem tissue, red beet, and potato discs (12,17), closely parallels its effect on liposomes. Furthermore, the effects of filipin, in both the in vivo and the in vitro systems, can be overcome by cholesterol (12).An explanation of hormone action in terms of alterations in membrane permeability has been a perennially proposed possibility. In general, the concept has met with only very limited success, for several reasons, and most workers continue to concentrate on more "metabolic explanations." In this and succeeding papers the potential role of gibberellin as a regulator of membrane permeability will be explored. MATERIALS AND METHODSTo pre...

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“…Liposomes and hormones or other test compounds have generally been incubated within dialysis bags (3,21) but, in this work (with the exception of the experiment illustrated in Fig. 7 …”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The Influence of Gibberellic Acid on the Permeability of Model Membrane Systems

Wood

Paleg

1972

Plant Physiol.

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“…Operationally, the model membranes are separated by aqueous compartments which can trap various small molecules or ions, by virtue of the repulsive forces imposed on the membranes by the incorporation of either long-chain anions or longchain cations. These model membranes have been used to study the action of agents such as steroids, lytic proteins, and polyene antibiotics (26)(27)(28), which react with liposomes much as with natural membranes. More recently liposomes have been used to demonstrate the interaction of various complement components with membranes (29,30).…”

Section: Introductionmentioning

confidence: 99%

Interaction of immunoglobulins with liposomes.

Weissmann¹,

Brand²,

Franklin³

1974

J. Clin. Invest.

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A B S T R A C T Liposomes were used as model targets to test the effect of immunoglobulins on biomembranes. Heat-aggregated immunoglobulins (Ig) exceeded native immunoglobulins in their capacity to release anions and glucose from model liposomes (either lecithin-dicetylphosphate-cholesterol or lecithin-stearylamine-cholesterol in molar ratios of 7: 2: 1). This interaction was not dependent upon the presence of cholesterol in the membrane. Mild heat-aggregation (10 min at 61.50C) increased the membrane-perturbing activity of certain 1g. Activity varied among classes and subclasses: IgG > pooled IgG > IgG4> IgA, > IgGs. IgG2, IgA2 and IgM were inert. Fc fragments of IgG were as active as IgGi, whereas Fab fragments were inactive. Prolonging aggregation to 60 min destroyed the activity of 1g. Membrane-activity could not be induced in non-Ig molecules (such as bovine serum albumin) by 10 or 60 min heat-aggregation. Density gradient centrifugation of IgG, molecules indicated that membrane perturbing activity was associated with 15-20-s aggregates. Sepharose 4B chromatography demonstrated preferential interaction between cationic membranes and aggregated Ig, whereas anionic membranes interacted nonselectively with both native and aggregated Ig via salt-like interactions. One explanation for these data is that heat aggregation induces a conformational change in the Fc regions of certain Ig permitting them to interact with liposomes, presumably by enhancing their hydrophobic associations with membrane phospholipids.

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Flow cytometric analysis of membrane permeability properties influencing intracellular accumulation and efflux of fluorescein

et al. 1986

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A flow cytometric investigation has been made on the membrane permeability properties that mediate intracellular turnover of fluorogenic substrates. The accumulation and efflux of fluorescein, consequent to the enzymatic turnover of fluorescein diacetate, were assessed in the presence of metabolic inhibitors and after treatment with membrane-active compounds.The metabolic poisons KCN and rotenone greatly inhibited only the fluorescein efflux, reducing the rate constant to as little as onetenth in relation to control cells; in the presence of glucose such inhibition was partially removed.Glucose availability also affected fluorescein efflux: an increase of the rate constant was observed in cells treated with 20 mM glucose, and a decrease was measured in cells incubated for 1 hr in glucose-free buffer.Membrane-active compounds Triton X-100 and hydrocortisone reduced fluorescein accumulation. Hydrocortisone strongly blocked also the efflux; the addition of glucose did not restore the rate significantly.The major evidence of these results is that fluorescein efflux is dependent on membrane integrity and on availability of metabolic energy. Fluorescein accumulation is only partially related to permeability properties regulating FDA uptake, due to the influence that treatments exhibit at the same time on FDA hydrolysis and/or fluorescein release.Key terms: Fluorescein diacetate, membrane permeability, flow cytometry, metabolic inhibitors, membrane-active agentsThe intracellular turnover of fluorogenic substrates is a valuable method for assessing membrane properties when the fluorescent product obtained after enzymatic hydrolysis is accumulated in living cells. Conversion of the substrate fluorescein diacetate (FDA) to the product fluorescein was first described by Rotman and Papermaster, and called fluorochromasia (8). FDA was shown to be useful for studying membrane permeability prop erties, since the intracellular accumulation of the fluorescent product was found to be dependent on the integrity of the cell membrane. Indeed, treatments with surface-active agents, freezing, aging, and the like were shown to cause loss of fluorochromasia (8).The mechanism proposed to explain this phenomenon was based on the finding that the non-fluorescent FDA, a non-polar compound, can easily enter the cell, where it is hydrolyzed to fluorescein. On the contrary, the fluorescent product, which is a polar molecule, cannot exit as fast as the substrate can enter; consequently, an intracellular fluorescence is observed. Agents that disrupt or severely damage the membrane will cause the fluorescein to diffuse out, so that fluorescence does not appear.Fluorochromasia was also used to study early changes of permeability properties, which do not necessarily involve severe damage to the membrane. This was possible because the kinetics of intracellular accumulation of the fluorescent product depends not only on enzyme activity, but also on the permeability characteristics of the substrate in entering the cells, as well as on the efflux rate ...

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Effect of Steroids and ‘Triton X-100’ on Glucose-Filled Phospholipid/cholesterol Structures

Cited by 41 publications

References 15 publications

The Influence of Gibberellic Acid on the Permeability of Model Membrane Systems

The Influence of Gibberellic Acid on the Permeability of Model Membrane Systems

Interaction of immunoglobulins with liposomes.

Flow cytometric analysis of membrane permeability properties influencing intracellular accumulation and efflux of fluorescein

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