Control by TSH of a phospholipase A<sub>2</sub> activity, a limiting factor in the biosynthesis of prostaglandins in the thyroid

Haye, Bernard; Champion, Serge

doi:10.1016/0014-5793(73)80664-7

Cited by 107 publications

(19 citation statements)

References 29 publications

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“…Arachidonate does not stimulate the cyclic AMP system of these cells but indomethacin partially inhibits the TSH stimulation of the cyclic AMP as we already described in pig thyroid slices [6] (fig.2). …”

Section: Statistical Evaluationsupporting

confidence: 64%

“…In [ll] we demonstrated a lack of correlation between the increase in the free arachidonate pool and its incorporation into prostaglandins. In [I 2 ,I 31 our results [6] on the PC production under an acute TSH stimulation of the phosphatidylinositol (PI) metabolism were confirmed. Specific PI phospholipases demonstrated and characterized in pig thyroid plasma membranes [ 12,131. So the arachidonate liberated by the hormone action: 1.…”

Section: Discussionmentioning

confidence: 87%

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Effects of arachidonate on cultured pig thyroid cells and their stimulation by thyrotropin

Gérard¹,

Haye²

1981

FEBS Letters

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1. Introduction ture at 37°C in 95% air-5% CO2 water-satured atmosphere with or without TSH. Arachidonate has been reported to interfere in complex fashion with the metabolism of the dog thyroid gland [l]. As in numerous other tissues arachidonate stimulates prostaglandin synthesis but with a low conversion rate. Moreover, in thyroid it depresses the accumulation of cyclic AMP induced by TSH. Arachidonate inhibits the thyroid secretion stimulated by low concentrations of TSH but enhances the iodination of proteins in dog thyroid slices. These effects do not depend on prostaglandin conversion, the decrease in the stimulation of adenylate cyclase is likely to be due to the unsaturated character of the fatty acid but it has been suggested that the stimulation of thyroid protein iodination is a consequence of an increase in lipoxygenase activity. Our purpose was to extend these studiesfurther to cultured pig thyroid cells in various physiological controled states and to draw a particular attention to phospholipid metabolism, protein iodination and cyclic AMP stimulation.

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Section: Statistical Evaluationsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 87%

Effects of arachidonate on cultured pig thyroid cells and their stimulation by thyrotropin

Gérard¹,

Haye²

1981

FEBS Letters

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“…Injection or infusion of the precursor arachidonic acid into the preparation also leads to the generation of prostaglandin endoperoxides and TXA2, (Vargaftig & Dao Hai, 1972;Palmer et al, 1973;Hamberg & Samuelsson, 1974) and it has therefore been inferred that 'substrate availability' is an important rate-limiting step in this reaction, and that agents which release these fatty acid derivatives do so by liberating the substrate from some endogenous lipid pool. The arachidonate content of most cells is high but little arachidonic acid is present in the 'free' form (Kunze & Vogt, 1971;Samuelsson, 1972;Haye, ' Present address: Rudolf Magnus Institute for Pharmacology, Vondellaan 6, Utrecht, The Netherlands.…”

Section: Introductionmentioning

confidence: 99%

“…Champion & Jacquemin, 1973). This 'lipid pool' must therefore comprise neutral lipid esters of arachidonic acid (mono-di-or tri-glycerides or cholesterol esters), or else the phospholipid store.…”

Section: Introductionmentioning

confidence: 99%

PHOSPHOLIPASE A₂ ACTIVITY OF GUINEA‐PIG ISOLATED PERFUSED LUNGS: STIMULATION, AND INHIBITION BY ANTI‐INFLAMMATORY STEROIDS

Blackwell

Flower

Nijkamp

et al. 1978

British J Pharmacology

303

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1 A simple double-isotope assay for phospholipase A2 activity of perfused organs is described. 2 Guinea-pig lungs perfused through the pulmonary circulation exhibit a low background enzyme activity. This activity is blocked by dexamethasone, betamethasone and hydrocortisone, mepacrine, procaine or chlorpromazine. Aspirin and indomethacin are without effect. 3 Mechanical trauma, antigen challenge or injections of bradykinin, rabbit aorta contracting substance-releasing factor (RCS-RF) or histamine increase 'basal' phospholipase activity. The effect of these agents, except that of bradykinin, is blocked by dexamethasone or mepacrine. 4 The blocking effect of steroids is cumulative and dose-dependent. They do not work in cell-free systems. Inhibition by mepacrine is rapid and is effective in cell-free lung homogenates. 5 It is suggested that agents which liberate prostaglandin endoperoxides and thromboxane A2 from perfused lungs do so by activating phospholipase A2.

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“…This offers an idea that PGI2 could mediate TSH action. In [3,4] TSH was shown to acutely stimulate prostaglandin E2(PGE2) synthesis but their results could not be confirmed in [5]. Thus acute effect of TSH on PGE2 synthesis was also studied and it is concluded that TSH acutely stimulates PGE2 synthesis.…”

Section: Introductionmentioning

confidence: 99%

Increases of prostacyclin and PGE₂ levels after acute thyrotropin stimulation in cultured porcine thyroid cells

et al. 1981

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Control by TSH of a phospholipase A₂ activity, a limiting factor in the biosynthesis of prostaglandins in the thyroid

Cited by 107 publications

References 29 publications

Effects of arachidonate on cultured pig thyroid cells and their stimulation by thyrotropin

Effects of arachidonate on cultured pig thyroid cells and their stimulation by thyrotropin

PHOSPHOLIPASE A₂ ACTIVITY OF GUINEA‐PIG ISOLATED PERFUSED LUNGS: STIMULATION, AND INHIBITION BY ANTI‐INFLAMMATORY STEROIDS

Increases of prostacyclin and PGE₂ levels after acute thyrotropin stimulation in cultured porcine thyroid cells

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Control by TSH of a phospholipase A2 activity, a limiting factor in the biosynthesis of prostaglandins in the thyroid

Cited by 107 publications

References 29 publications

Effects of arachidonate on cultured pig thyroid cells and their stimulation by thyrotropin

Effects of arachidonate on cultured pig thyroid cells and their stimulation by thyrotropin

PHOSPHOLIPASE A2 ACTIVITY OF GUINEA‐PIG ISOLATED PERFUSED LUNGS: STIMULATION, AND INHIBITION BY ANTI‐INFLAMMATORY STEROIDS

Increases of prostacyclin and PGE2 levels after acute thyrotropin stimulation in cultured porcine thyroid cells

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Product

Resources

About

Control by TSH of a phospholipase A₂ activity, a limiting factor in the biosynthesis of prostaglandins in the thyroid

PHOSPHOLIPASE A₂ ACTIVITY OF GUINEA‐PIG ISOLATED PERFUSED LUNGS: STIMULATION, AND INHIBITION BY ANTI‐INFLAMMATORY STEROIDS

Increases of prostacyclin and PGE₂ levels after acute thyrotropin stimulation in cultured porcine thyroid cells