Indomethacin treatment causes loss of insulin action in rats: involvement of prostaglandins in the mechanisms of insulin action

Wasner, H.K.; Weber, Sabine; Partke, Hans-Joachim; Amini-Hadi-Kiashar, H.

doi:10.1007/bf00571947

Cited by 24 publications

(29 citation statements)

References 52 publications

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“…Some prostanoids are ligands of PPAR receptors (101,102), and PPARs are implicated in the regulation of apo A-I expression (103,104). In addition, prostanoids interfere with insulin action, an important modulator of apo A-I gene expression (105,106). Thus, it is possible that prostanoids may have a role in modulating apo A-I expression.…”

Section: Effect Of Fat Metabolites: Ketones and Prostanoidsmentioning

confidence: 96%

The Effect of Select Nutrients on Serum High-Density Lipoprotein Cholesterol and Apolipoprotein A-I Levels

2005

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One of the factors contributing to the increased risk of developing premature atherosclerosis is low plasma concentrations of high-density lipoprotein (HDL) cholesterol (HDLc). Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein A-I (apo A-I). The low plasma concentrations of HDL could be the result of increased fractional clearance and reduced expression of apo A-I. To this end, nutrients play an important role in modulating the fractional clearance rate, as well as the rate of apo A-I gene expression. Because medical nutrition therapy constitutes the cornerstone of management of dyslipidemias, it is essential to understand the mechanisms underlying the changes in HDL level in response to alterations in dietary intake. In this review, we will discuss the effect of select nutrients on serum HDLc and apo A-I levels. Specifically, we will review the literature on the effect of carbohydrates, fatty acids, and ketones, as well as some of the nutrient-related metabolites, such as glucosamine and the prostanoids, on apo A-I gene expression. Because there are multiple mechanisms involved in the regulation of serum HDLc levels, changes in gene transcription do not necessarily correlate with clinical observations on serum levels of HDLc.

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Section: Effect Of Fat Metabolites: Ketones and Prostanoidsmentioning

confidence: 96%

The Effect of Select Nutrients on Serum High-Density Lipoprotein Cholesterol and Apolipoprotein A-I Levels

2005

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“…Prostanoids are implicated in insulin signaling in the liver (48,49). Therefore, it is possible that interference with prostanoid production within the liver may alter insulin effects on apo A-I expression.…”

Section: Effect Of Insulin Resistance On Apo A-i Expressionmentioning

confidence: 99%

Transcriptional Control of Apolipoprotein A-I Gene Expression in Diabetes

2004

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Cardiovascular disease continues to be the leading cause of mortality in diabetes. One of the factors contributing to the increased risk is the high prevalence rate of low plasma concentrations of HDL cholesterol. Multiple potential mechanisms account for the cardioprotective effects of HDL and its main protein apolipoprotein (apo) A-I. The reduced plasma concentrations of HDL could be the result of increased fractional clearance of HDL and reduced expression of apo A-I. In animal models of diabetes and in cell cultures treated with high concentrations of glucose, apo A-I expression is reduced. In this review we will discuss the alterations in transcriptional control of apo A-I in diabetes. The role of select nutritional and hormonal alterations commonly found in diabetes will be reviewed. Specifically, we will review the literature on the effect of hyperglycemia, hypoinsulinemia, and ketoacidosis, as well as the role of various mediators of insulin resistance, such as fatty acids, cytokines, and prostanoids, on apo A-I promoter activity. Identifying the mechanisms that modulate apo A-I gene expression will aid in the new development of therapeutic agents that increase plasma apo A-I and HDL concentrations.

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“…Cyclic PIP-deficiency, caused by inhibition of cyclooxygenase by indomethacin, leads to high plasma insulin levels as a result of increased insulin release from pancreatic ␤-cells, and also leads to insulin resistance of peripheral tissues, characterized by deprived glycogen stores in the liver and reduced activation of glucose transport into iso-lated adipocytes, i. e. it results in a metabolic state comparable to type II diabetes (Wasner et al, 1994). In diabetic animals, like Ksj db/db mice, diabetic BB rats and also in SHR rats, a reduced cyclic PIP synthase activity could be demonstrated (Wasner et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Two Different Mechanisms for Activation of Cyclic PIP Synthase: by a G Protein or by Protein Tyrosine Phosphorylation

Wasner¹,

Gebel²,

Hucken³

et al. 2000

Biological Chemistry

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The biosynthesis of the functional, endogenous cyclic AMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP) is performed by the plasma membrane-bound enzyme cyclic PIP synthase, which combines prostaglandin E (PGE) and activated inositol phosphate (n-IP) to cyclic PIP. The Km values of the enzyme for the substrates PGE and n-IP are in the micromolar range. The plasma membrane-bound synthase is activated by fluoride, by the stable GTP analog GMP-PNP, by protamine or biguanide, by noradrenaline, and by insulin. The activation by protamine or biguanide and fluoride (10 mM) is additive, which may indicate the presence of two different types of enzyme, comparable to phospholipase Cbeta and phospholipase Cgamma. Plasma membrane-bound cyclic PIP synthase is inhibited by the protein tyrosine kinase inhibitor tyrphostin B46 with an IC50 of 1.7 microM. However, the solubilized and gel-filtrated enzyme is no longer inhibited by tyrphostin, indicating that the activity of cyclic PIP synthase is connected with the activity of a membrane-bound protein tyrosine kinase. Cyclic PIP synthase activity of freshly prepared plasma membranes is unstable. Upon freezing and rethawing of liver plasma membranes, this instability is increased about 2-fold. Protein tyrosine phosphatase inhibitors [vanadate, fluoride (50-100 mM)] stabilize the enzyme activity, but protease inhibitors do not, indicating that inactivation of the enzyme is connected with protein tyrosine dephosphorylation. Cyclic PIP synthase is present in all tissues tested, like brain, heart, intestine, kidney, liver, lung, skeletal muscle, spleen, and testis. Apart from liver, cyclic PIP synthase activity in most tissues is rather low, but it can be increased up to 5-fold when protein tyrosine phosphatase inhibitors like vanadate are present in the homogenization buffer. Preincubation of cyclic PIP synthase of liver plasma membranes with the tyrosine kinase src kinase causes a 2-fold increase of cyclic PIP synthase activity, though this is certainly not the physiological role played by src kinase in intact cells. The data indicate that cyclic PIP synthase can be activated by two separate mechanisms: by a G protein or by protein tyrosine phosphorylation.

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Indomethacin treatment causes loss of insulin action in rats: involvement of prostaglandins in the mechanisms of insulin action

Cited by 24 publications

References 52 publications

The Effect of Select Nutrients on Serum High-Density Lipoprotein Cholesterol and Apolipoprotein A-I Levels

The Effect of Select Nutrients on Serum High-Density Lipoprotein Cholesterol and Apolipoprotein A-I Levels

Transcriptional Control of Apolipoprotein A-I Gene Expression in Diabetes

Two Different Mechanisms for Activation of Cyclic PIP Synthase: by a G Protein or by Protein Tyrosine Phosphorylation

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