Bovine lens epithelium: A suitable model for studying growth control mechanisms

Glässer, D; Rattke, W.; Iwig, M

doi:10.1016/0014-4827(79)90305-7

Cited by 15 publications

(8 citation statements)

References 24 publications

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“…When we searched for facts which would help to elucidate the mode of action of these substances we found them to be inhibitors of the uptake of calcium-45 with a specificity that corresponds very well with their flattening retarding capacity: adenine, most effective in retarding cell flattening, is also most effective in inhibiting the uptake of calcium-45, hypoxanthine and guanine about equally effective in both test systems, while the closely related xanthine and 6-mercaptopurine are without effects in both test systems [3], These findings certainly support the assumption of an increased calcium uptake as a primary stimulus for the activation of resting in vivo cells.…”

Section: Resultsmentioning

confidence: 97%

“…Obviously in vitro cells -even if in a resting state -are ready for flattening but in vivo cells must be activated before. Some years ago we described typical moving phenomena within the lens epithelium during the first hours in primary culture which precede the onset of DNA synthesis by many hours [2,3], They start by a retraction of the monolayered epithelium leading to multilayered aggregates. Later on.…”

Section: Resultsmentioning

confidence: 99%

“…the aggregates are respread resulting in very flattened cells. It has been estab lished in detail recently that the retraction phenomenon can be taken for a morphological indicator announcing an increasing calcium influx into the cells as a very early event in the primary culture [3], and the following re spreading and cell flattening has been recognized as indispensable steps towards DNA synthesis in resting lens cells [5].…”

Section: Resultsmentioning

confidence: 99%

“…The methods and the materials used have been described in detail elsewhere [3]. If necessary, they are given briefly in the legends.…”

Section: Methodsmentioning

confidence: 99%

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Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G₀Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Glässer¹,

Rattke²,

Iwig³

1979

Ophthalmic Res

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Cell flattening is a powerful stimulus for switching on DNA synthesis and mitotic growth. While resting lens cells already kept in vitro are ready for flattening, lens cells which have been in a resting state in vivo must be activated before. Adenine, hypoxanthine, and guanine prove to be specific inhibitors of this activation. Their mode of action point at calcium as a primary stimulus and phosphoribosylpyrophosphate as a second substance involved in the activating mechanism.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…The methods and the materials used have been described in detail elsewhere [3]. If necessary, they are given briefly in the legends.…”

Section: Methodsmentioning

confidence: 99%

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Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G₀Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Glässer¹,

Rattke²,

Iwig³

1979

Ophthalmic Res

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“…Details of the procedure have been described elsewhere (Glaesser & Iwig, 1975;Glaesser et al (1979a). Briefly, pieces of the central part of the anterior lens capsule were cut out, attached to a cover slide by capillary forces and immediately transferred to a Petri dish containing 4 ml of HBS.…”

Section: Primary Culture and Quantitative Evaluation Of Moving Phenomenamentioning

confidence: 99%

Alkalinization Stimulates Ca²⁺‐Dependent Spreading During the Activation of Resting Lens Epithelial Cells In Primary Culture

et al. 1984

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Lens epithelium, when attached to its natural substratum, the lens capsule, can be maintained in culture for more than 2 weeks in a simple HEPES‐ and EDTA‐buffered salt solution (HBS). In HBS, the epithelium shows the same characteristic phenomena of locomotion, initial retraction and respreading which in MEM plus serum precedes the inception of DNA synthesis. These phenomena have been shown to be dependent on extracellular Ca2+. 0·05 mM Ca2+ is necessary for maintaining cell‐to‐cell contacts of the in vivo epithelium. Higher concentrations of Ca2+ cause the epithelium to retract initially. In contrast, Mg2+ greatly favours cell‐substratum interactions leading to the formation of lamellopodia and an initial spreading of the epithelium. After some hours in culture the epithelium changes markedly in response to extracellular Ca2+ and Mg2+; it respreads and flattens in the presence of Ca2+, while Mg2+ becomes less effective in maintaining cell‐to‐substratum contacts. Mg2+‐dependent initial spreading is promoted at pH values near 7·0 but the Ca2+‐dependent respreading requires an alkalinization of the salt solution.

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Nutrient transport in a bovine lens epithelial cell line

Prasad

Shopsis

Southern

et al. 1981

Journal Cellular Physiology

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A bovine calf lens epithelial cell line (CLE-1) that synthesizes crystallin has been established in culture and some of its transport properties have been characterized using both cells and membrane vesicles derived from them. The membrane vesicles fractionate with high recovery of plasma membrane markers, showing a 40-fold purification of 5'-AMPase and a 20-fold decrease in the specific activity of the mitochondrial marker enzyme succinic dehydrogenase relative to a cell homogenate. Transport sites demonstrated higher specific activity than has been seen in vesicles from cell lines studied previously. The uptake of alpha-amino isobutyric acid (AIB) (an alanine analog) by CLE-1 cells is stimulated four- to fivefold by Na+ and exhibits a Km of 5.4 mM with a Vmax of 50 pmoles/min.microgram of cell protein. The uptake of leucine was not Na+ stimulatable. The uptake of AIB by the cells was reduced by 43% at confluence. Thus, the cell density dependent behavior of the uptake of the alanine amino acid family in CLE-1 is similar to that of various fibroblast cells. The Na+ caused a threefold stimulation of AIB uptake in the membrane vesicles, while vesicular uptake of leucine was unaffected by Na+. The uptake of adenine, guanine, uridine, and guanosine was also tested in these vesicles. The substrates were rapidly accumulated, came to a steady state distribution within 1-2 minutes, and were recovered as the unaltered compounds after uptake.

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Bovine lens epithelium: A suitable model for studying growth control mechanisms

Cited by 15 publications

References 24 publications

Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G₀Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G₀Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Alkalinization Stimulates Ca²⁺‐Dependent Spreading During the Activation of Resting Lens Epithelial Cells In Primary Culture

Nutrient transport in a bovine lens epithelial cell line

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Bovine lens epithelium: A suitable model for studying growth control mechanisms

Cited by 15 publications

References 24 publications

Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G0Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G0Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Alkalinization Stimulates Ca2+‐Dependent Spreading During the Activation of Resting Lens Epithelial Cells In Primary Culture

Nutrient transport in a bovine lens epithelial cell line

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Product

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Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G₀Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Low Doses of Exogenous Adenine, Hypoxanthine, and Guanine Hold G₀Cells from Bovine Lens Epithelium in the Resting State by Inhibiting Cell Flattening

Alkalinization Stimulates Ca²⁺‐Dependent Spreading During the Activation of Resting Lens Epithelial Cells In Primary Culture