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PubMed1999

High ovulatory rates with use of troglitazone in clomiphene-resistant women with polycystic ovary syndrome.

This preliminary report reviews our experience with 18 infertile patients with clomiphene-resistant polycystic ovary syndrome (PCOS). In the first treatment cycle, troglitazone was administered alone. During cycles 2-5, clomiphene was added with increments of 50 mg (up to 200 mg/day) if the previous cycle was anovulatory. Basal body temperature charts and serum progesterone were obtained to confirm ovulation. In a total of 66 treatment cycles, ovulation occurred in 44 (67%) and pregnancy in seven (11%). There were no significant changes in body weight, waist:hip ratio or liver enzymes during treatment. Troglitazone, alone or with clomiphene, induced ovulation in 15 of 18 patients (83%) and seven (39%) of them achieved pregnancy. This is the first report on ovulatory rates in clomiphene-resistant women with PCOS when troglitazone was used alone or with clomiphene. Recently, metformin and clomiphene were successfully used in women with PCOS. However, our patients represent a more resistant population of women with PCOS, with each patient serving as her own historical control by previous resistance to clomiphene. Although the pregnancy rate (39%) was promising for clomiphene-resistant women with polycystic ovary syndrome, it does not seem to have a definite advantage over gonadotrophins.

Adult↗
PubMed2004

Improvement of insulin resistance by troglitazone ameliorates cardiac sympathetic nervous dysfunction in patients with essential hypertension.

BACKGROUND: It was recently suggested that insulin resistance is significantly correlated with activation of the cardiac sympathetic nervous system in patients with essential hypertension. OBJECTIVES: To examine the effects of troglitazone, an agent used to treat insulin resistance, on cardiac sympathetic nervous dysfunction and insulin resistance in patients with essential hypertension. METHODS: The study participants included 34 patients (14 men, 20 women) with mild essential hypertension and 17 normal controls (group C, seven men). The patients were randomly divided into two groups, one treated with 400 mg troglitazone and antihypertensive drugs (group T, n = 17) and the other treated with antihypertensive drugs only (group N, n = 17). We evaluated insulin resistance and cardiac sympathetic nervous function before and after 6 months of treatment. Insulin resistance was evaluated using steady-state plasma glucose (SSPG; mg/dl) concentrations and cardiac sympathetic nervous function was evaluated using the heart-to-mediastinum ratio (H : M) and mean washout rate measured by 123I-meta-iodobenzylguanidine (MIBG) cardiac imaging. RESULTS: There were significant differences in SSPG (P < 0.01), early (P < 0.05) and delayed (P < 0.05) phases of H : M and washout rate (P < 0.05) between the hypertensive patients and group C. The SSPG concentration was significantly improved after treatment only in group T, from 153.3 to 123.7 mg/dl (P < 0.01). The early and delayed phases of H : M and washout rate also were significantly improved (P < 0.05) (from 2.59 to 2.63, from 2.12 to 2.27 and from 18.1 to 13.7%, respectively) in only group T.The change in SSPG was significantly correlated with the changes in H : M and washout rate (r = -0.639 and 0.577, respectively). CONCLUSION: Troglitazone had a beneficial effect on cardiac sympathetic nervous function through a decrease in insulin resistance in patients with essential hypertension.

Antihypertensive Agents↗
PubMed2006

Troglitazone, a peroxisome proliferator-activated receptor-gamma agonist, decreases tau phosphorylation in CHOtau4R cells.

Peroxisome proliferator-activated receptor-gamma (PPARgamma), a member of the nuclear receptor superfamily, is activated by several compounds including the thiazolidinediones. In addition to being a target for diabetes, PPARgamma activation state has recently been shown to modulate beta-amyloid peptide (Abeta) production in cellular models relevant to Alzheimer's disease. Here, we report the effect of troglitazone, a thiazolidinedione, in cells expressing 4-repeat tau. A 24 h treatment with troglitazone significantly reduced phosphorylation of tau at Ser202 and Ser396/404, residues of early and later stages of neurofibrillary tangle accumulation in Alzheimer's disease and other neurodegenerative disorders. Under the same experimental conditions the level of tau did not change. In our cellular model, troglitazone appeared to enhance 3'-phosphoinositide-dependent protein kinase 1 (PDK1) nuclear translocation, resulting in a decrease in cytosolic phosphorylated 70 kDa ribosomal protein kinase (p70S6) and phosphorylated mammalian target of rapamycin (mTor). Furthermore, PPARgamma transcriptional activity did not appear to be responsible for decreased phosphorylation of tau. Thus, we believe that the thiazolidinedione regulates tau phosphorylation through a PPARgamma-dependent/independent mechanism involving an Akt/glycogen synthase kinase-3(GSK-3beta)-independent signalling cascade: PDK1/p70S6K/mTor.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed2001

A pilot study of a thiazolidinedione, troglitazone, in nonalcoholic steatohepatitis.

OBJECTIVES: Troglitazone is a thiazolidinedione and peroxisome proliferator-activated receptor gamma (PPARgamma) ligand used to treat diabetes mellitus type II. Because hyperinsulinemia may be a factor in nonalcoholic steatohepatitis (NASH), we postulated that troglitazone could have beneficial effects in this disorder. Our study was initiated before reports of idiosyncratic hepatitis induced by this agent and was completed before its recent withdrawal from the market. METHODS: We studied 10 female patients (age 44 +/- 16) with histological NASH. All but two were obese (mean body mass index, BMI = 38 +/- 6). One had type 2 diabetes, and three had well-compensated cirrhosis with NASH. Troglitazone was given at a dose of 400 mg/day for < or = 6 months. Responders (defined as normal ALT at the end of treatment) were rebiopsied. Paired specimens were compared in blinded fashion. Mitochondria were quantitated using ultrathin electron microscopy. RESULTS: Seven of ten patients responded with normal ALT at the end of treatment. One of three nonresponders initially normalized ALT but returned to pretreatment level at 3 months. In this patient, therapy was stopped, and the ALT has remained at the baseline level with no other clinical or laboratory findings. In the responders, ALT fell from 87 +/- 38 before to 39 +/- 9 at the end of treatment (p = 0.01), and AST decreased from 77 +/- 23 to 30 +/- 8 (p = 0.002). Biopsy comparisons before and after therapy showed persistent steatohepatitis in all cases, although four of seven showed a one-point improvement in the necroinflammatory grade. Electron microscopy revealed elongation of the mitochondria after therapy. CONCLUSIONS: Normal ALT was seen in 70% of NASH patients at the end of treatment, but this biochemical response was associated with only mild histological improvement, and all follow-up biopsies had evidence of NASH. Normalization of the liver enzymes in patients with NASH who are treated with thiazolidinediones should be viewed with reservation. Follow-up biopsy is essential to evaluate the efficacy of these agents, which, at the histological level, appears to be relatively modest.

Adult↗
PubMed1996

Prevention of hyperglycemia in the Zucker diabetic fatty rat by treatment with metformin or troglitazone.

To determine whether metformin or troglitazone can delay the onset of diabetes in the Zucker diabetic fatty (ZDF) rat, lean control, fatty, and ZDF rats received metformin, troglitazone, or no treatment from 6 to 12 wk of age. Glucose, insulin, triglyceride (TG), and free fatty acid (FFA) levels and glucose stimulated insulin secretion by the perfused pancreas were measured. Metformin-treated rats gained significantly less weight. Both drugs prevented hyperglycemia by 12 wk in diabetic rats and significantly reduced TG and FFA levels. Insulin secretion at low glucose was elevated in untreated fatty and diabetic animals, and the increment in diabetic animals produced by glucose perfusion was attenuated compared with lean and fatty rats. Both drugs reduced basal insulin secretion in fatty and diabetic rats and improved glucose responsiveness in diabetic rats. Metformin and troglitazone delay the onset of diabetes in the ZDF rat. The significantly improved insulin secretory response of the pancreas undoubtedly contributes to the improved glucose tolerance.

Age Factors↗
PubMedDate not supplied

Troglitazone combination therapy in obese type 2 diabetic patients poorly controlled with alpha-glucosidase inhibitors.

The efficacy and safety of treatment with troglitazone combined with an alpha-glucosidase inhibitor, in obese type 2 diabetic patients who were previously administered alpha-glucosidase inhibitors alone, in improving glycaemic control and reducing insulin resistance were studied. Obese type 2 diabetic patients, poorly controlled with alpha-glucosidase inhibitors, were randomized to receive either oral troglitazone 200 mg twice daily (22 patients: group A) or a placebo (20 patients: group B) in addition to their usual alpha-glucosidase inhibitor. In group A, significant decreases in the mean levels of haemoglobin A1c and basal plasma insulin levels were observed 6 months after the start of combined therapy. Serum triglyceride levels significantly decreased but serum lactic acid dehydrogenase and body weight significantly increased. New systemic oedema was observed in six patients. Combined therapy with troglitazone and alpha-glucosidase inhibitors may be effective for diabetic metabolic abnormalities, although the potential development of adverse effects such as body-weight gain and systemic oedema demands vigilance.

Acarbose↗
PubMed2003

Impaired expression of NADH dehydrogenase subunit 1 and PPARgamma coactivator-1 in skeletal muscle of ZDF rats: restoration by troglitazone.

Type 2 diabetes has been related to a decrease of mitochondrial DNA (mtDNA) content. In this study, we show increased expression of the peroxisome proliferator-activated receptor-alpha (PPARalpha) and its target genes involved in fatty acid metabolism in skeletal muscle of Zucker Diabetic Fatty (ZDF) (fa/fa) rats. In contrast, the mRNA levels of genes involved in glucose transport and utilization (GLUT4 and phosphofructokinase) were decreased, whereas the expression of pyruvate dehydrogenase kinase 4 (PDK-4), which suppresses glucose oxidation, was increased. The shift from glucose to fatty acids as the source of energy in skeletal muscle of ZDF rats was accompanied by a reduction of subunit 1 of complex I (NADH dehydrogenase subunit 1, ND1) and subunit II of complex IV (cytochrome c oxidase II, COII), two genes of the electronic transport chain encoded by mtDNA. The transcript levels of PPARgamma Coactivator 1 (PGC-1) showed a significant reduction. Treatment with troglitazone (30 mg/kg/day) for 15 days reduced insulin values and reversed the increase in PDK-4 mRNA levels, suggesting improved insulin sensitivity. In addition, troglitazone treatment restored ND1 and PGC-1 expression in skeletal muscle. These results suggest that troglitazone may avoid mitochondrial metabolic derangement during the development of diabetes mellitus 2 in skeletal muscle.

Animals↗
PubMed1994

Troglitazone prevents the inhibitory effects of inflammatory cytokines on insulin-induced adipocyte differentiation in 3T3-L1 cells.

Tumor necrosis factor (TNF) is implicated in wasting syndromes and insulin resistance in chronic infection and obese-linked diabetes. TNF (10 ng/ml) inhibited adipocyte differentiation of 3T3-L1 cells, and in these TNF treated cells little insulin-stimulated glucose uptake was observed. Treatment of 3T3-L1 cells with troglitazone (1-10 microM) partially prevented this inhibitory effect of TNF on adipogenesis, and enhanced expression of C/EBP alpha and GLUT4, even in the presence of TNF. Troglitazone also prevented the inhibitory effects of interleukin-1, interleukin-6, and leukemia inhibitory factor, but not of transforming growth factor beta on adipocyte differentiation of 3T3-L1 cells. These effects might contribute to the antidiabetic effect of troglitazone in obese diabetic animals.

3T3 Cells↗
PubMed2003

Minimal response of circulating lipids in women with polycystic ovary syndrome to improvement in insulin sensitivity with troglitazone.

We hypothesized that the administration of troglitazone (TGZ), an insulin-sensitizing agent of the thiazolidinedione class, would improve dyslipidemia associated with insulin resistance in polycystic ovary syndrome (PCOS). Three hundred and ninety-eight women with PCOS in a multicenter, double-blind trial were randomly assigned to 44 wk of treatment with: placebo or troglitazone (150, 300, or 600 mg/d). We examined the responses of circulating lipid and lipoproteins [total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglycerides (TTG)] by treatment arm, and the influence of glycemic parameters on baseline levels and response to treatment. There was a high prevalence of abnormal baseline lipid parameters, as defined by National Cholesterol Education Program guidelines [total cholesterol, > or = 200 mg/dl (35%); LDL-C, > or = 130 mg/dl (31%); HDL-C, <35 mg/dl (15%); TTG, >200 mg/dl (16%)]. Baseline models showed that parameters of insulin action had poor predictive power on lipid parameters. There was no significant response of any of the circulating lipids to treatment with either placebo or one of the troglitazone arms (after correction for multiple analyses). There were favorable, but nonsignificant, trends in HDL-C (increase) and LDL-C (decrease) and a trend toward decreased circulating TTG in the 300- and 600-mg TGZ dose treatment arms, both in an intention to treat analysis (n = 375) and in study completers (44 wk; n = 152). There also was a minimal treatment effect noted when only subjects with abnormal baseline levels were examined, and responders differed little from nonresponders in terms of indices of insulin action. There is a substantial prevalence of clinically recognized dyslipidemia in the population of women with unrecognized PCOS without type 2 diabetes. Treatment with an insulin-sensitizing agent may have minimal impact on circulating lipids. Further surveillance and treatment of abnormal lipid levels may be necessary in these women.

Adult↗
PubMed2001

Suppression of nuclear factor-kappaB and stimulation of inhibitor kappaB by troglitazone: evidence for an anti-inflammatory effect and a potential antiatherosclerotic effect in the obese.

To elucidate whether troglitazone exerts an antiinflammatory effect in humans, in vivo, we investigated the suppression of nuclear factor kappaB (NFkappaB) in mononuclear cells (MNC) by this drug. We measured intranuclear NFkappaB, total cellular NFkappaB, inhibitor kappaB (IkappaB)alpha, reactive oxygen species (ROS) generation, and p47(phox) subunit (a key component protein of nicotinamide adenine dinucleotide phosphate oxidase) in MNC. Plasma tumor necrosis factor (TNF)-alpha, soluble intercellular adhesion molecule-1 (sICAM-1), monocyte chemoattractant protein-1 (MCP-1), plasminogen activator inhibitor type 1 (PAI-1), C-reactive protein (CRP), and interleukin (IL)-10 (antiinflammatory cytokine) concentrations were also measured as mediators of inflammatory activity that are regulated by the proinflammatory transcription factor NFkappaB. Seven nondiabetic obese patients were given 400 mg troglitazone daily for 4 weeks. Blood samples were collected before and at weekly intervals thereafter. MNC were separated; and the levels of intranuclear NFkappaB, total cellular NFkappaB, IkappaBalpha, and p47 (phox) subunit and ROS generation were determined. Plasma was used to measure insulin glucose, TNFalpha, sICAM, MCP-1, PAI-1, CRP, and IL-10. Plasma insulin concentrations fell significantly at week 1, from 31.2 +/- 29.1 to 14.2 +/- 11.4 mU/L (P < 0.01) and remained low throughout 4 weeks. Plasma glucose concentrations did not alter significantly. There was a fall in intranuclear NFkappaB, total cellular NFkappaB, and p47 (phox) subunit, with an increase in cellular IkappaBalpha at week 2, which persisted until week 4. There was a parallel fall in ROS generation by MNC at week 1; this progressed and persisted until week 4 (P < 0.001). Plasma TNF-alpha, sICAM-1, MCP-1, and PAI-1 concentrations fell significantly at week 4. Plasma IL-10 concentration increased significantly, whereas plasma CRP concentrations decreased. We conclude that troglitazone has an antiinflammatory action that may contribute to its putative antiatherosclerotic effects.

Adult↗
PubMed2003

Physicochemical and crystal structure analyses of the antidiabetic agent troglitazone.

The antidiabetic agent troglitazone has two asymmetric carbons located at the chroman ring and the thiazolidine ring and is produced as a mixture of equal amounts of four optical isomers, 2R-5S, 2S-5R, 2R-5R, and 2S-5S. The crystalline powdered drug substance consists of two diastereomer pairs, 2R-5R/2S-5S and 2R-5S/2S-5R. There are many types of crystals obtained from various crystallization conditions. The X-ray structure analysis and the physicochemical analyses of troglitazone were performed. The solvated crystals of the 2R-5R/2S-5S pair were crystallized from several solutions: methanol, ethanol, acetonitrile, and dichloromethane. The ratio of solvent and troglitazone was 1 : 2 (L1/2-form). The monohydrate crystals were obtained from aqueous acetone solution (L1-form). On the other hand, only an anhydrate crystal of the 2R-5S/2S-5R pair was crystallized from various solutions (H0-form). The dihydrous mixed crystal (MA2-form) was obtained from a mixture of the two diastereomer pairs of 2R-5R/2S-5S and 2R-5S/2S-5R in equal amounts by the slow evaporation of aqueous acetone solution. The crystal structure of the MA2-form is similar to the H0-form. When the MA2 crystal was kept under low humidity, it was converted into the dehydrated form (MA0-form) with retention of the single crystal form. The structure of the MA0-form is isomorphous to the H0-form. The MA2-form was converted into the MA0-form and vice versa with retention of the single crystal under low and high humidity, respectively. The crystallization and storage conditions of the drug substances were successfully analyzed.

Chemical Phenomena↗
PubMed2001

Troglitazone improves endothelial function and augments renal klotho mRNA expression in Otsuka Long-Evans Tokushima Fatty (OLETF) rats with multiple atherogenic risk factors.

Targeted disruption of the klotho gene induces multiple phenotypes characteristic of human aging, including arteriosclerosis, pulmonary emphysema and osteoporosis. Moreover, we previously observed that insufficient klotho expression in mice leads to endothelial dysfunction. In the present study, we used Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which exhibit hypertension, obesity, severe hyperglycemia and hypertriglyceridemia, and are thus considered an animal model of atherogenic disease, to test the effects of oral administration of troglitazone (200 mg/kg) on renal klotho mRNA expression and endothelial function. Systolic blood pressure, body weight, plasma glucose and triglyceride levels were all significantly higher in 30-week-old OLETF rats than in controls (LETO; Long-Evans Tokushima Otsuka) (p<0.05, n=7). In addition, endothelium-dependent relaxation of the aorta in response to 10(-5) M acetylcholine was significantly attenuated in OLETF rats (p<0.05, n=7), as was renal expression of klotho mRNA. Administration of troglitazone for 10 weeks significantly reduced systolic blood pressure, plasma glucose and triglyceride levels in OLETF rats, while augmenting endothelium-dependent aortic relaxation and renal klotho mRNA expression. These findings suggest that troglitazone protects the vascular endothelium against damage caused by the presence of multiple atherogenic factors.

Animals↗
PubMed2004

Impact of safety warnings on drug utilization: marketplace life span of cisapride and troglitazone.

STUDY OBJECTIVE: To evaluate the impact of safety alerts on the volume of cisapride and troglitazone usage. DESIGN: Retrospective database analysis. SETTING: University research center. MATERIAL: Idaho Medicaid claims data from January 1994--July 2000. MEASUREMENTS AND MAIN RESULTS: Monthly counts of total and new prescriptions filled for cisapride and troglitazone were analyzed graphically over time as a function of all prescriptions. New prescriptions were defined as those filled by patients who had not received the drug within the previous year. A binomial comparison of the 5 months before and after each safety alert was conducted by Poisson distribution. Overall and new cisapride usage increased after the first alert, which occurred in February 1995 (p<0.05). After the second alert, in September 1995, growth in new prescriptions ended but total prescriptions continued to grow (p<0.05). After the third alert, in June 1998, growth in total use ended and the number of new prescriptions declined (p<0.05). The final two alerts (June 1999 and January 2000) were met with significant declines (p<0.05 for both). Troglitazone was the subject of two alerts in October and December 1997. After these, overall usage increased (p<0.05), whereas the number o new prescriptions decreased (p<0.05). The third alert, in July 1998, caused no change as total prescription use continued to grow (p<0.05), whereas the number of new prescriptions decreased (p<0.05). A fourth alert, in June 1999, resulted in a decrease of overall usage and new prescriptions (p<0.05 for both). CONCLUSION: Numerous safety alerts were required for each drug before drug usage declined. The decline in overall use was slower than the decline in new prescriptions, possibly indicating a need for increased assessment of refilled prescriptions after the release of new safety data.

Chromans↗
PubMed1999

Dehydroepiandrosterone suppresses the elevated hepatic glucose-6-phosphatase and fructose-1,6-bisphosphatase activities in C57BL/Ksj-db/db mice: comparison with troglitazone.

The effect of dehydroepiandrosterone (DHEA) on the hepatic and muscle glucose metabolizing enzymes and on blood glucose were investigated in insulin-resistant diabetic C57BL/KsJ-db/db mice and their heterozygote littermates (db/+m). The results were compared with those after troglitazone administration under the same conditions. Despite hyperinsulinemia, hepatic glucose-6-phosphatase (G6Pase) and fructose-1,6-bisphosphatase (FBPase) activities are higher in db/db than in db/+m mice. Dietary administration of DHEA and that of troglitazone for 15 days to respective groups of five mice each significantly decreased blood glucose in db/db mice and hepatic G6Pase and FBPase activities in both db/db and db/+m mice. Hepatic G6Pase and FBPase activities showed a linear relationship with blood glucose in all groups of mice, suggesting that the activities of G6Pase and FBPase are closely related to blood glucose levels. Because androstenedione, a DHEA metabolite, barely affected either of these enzyme activities or blood glucose in db/db mice, the actions of DHEA, which are similar to those of troglitazone, are presumed to be caused by DHEA itself. DHEA is considered to be a modulating agent for the activities of hepatic gluconeogenic enzymes in db/db mice.

Androstenedione↗
PubMed2000

Anti-inflammatory actions of 15-deoxy-delta 12,14-prostaglandin J2 and troglitazone: evidence for heat shock-dependent and -independent inhibition of cytokine-induced inducible nitric oxide synthase expression.

In this study, the anti-inflammatory actions of the peroxisome proliferator-activated receptor (PPAR)-gamma agonists 15-deoxy-delta 12,14-prostaglandin J2 (15-d-delta 12,14-PGJ2) and troglitazone have been examined. Treatment of RAW 264.7 cells and CD-1 mouse peritoneal macrophages with lipopolysaccharide (LPS) + interferon-gamma (IFN-gamma) results in inducible nitric oxide synthase (iNOS), inducible cyclooxygenase (COX-2) and interleukin-1 (IL-1) expression, increased production of nitric oxide, and the release of IL-1. In a concentration-dependent manner, 15-d-delta 12,14-PGJ2 inhibits each of these proinflammatory actions of LPS + IFN-gamma, with half-maximal inhibition at approximately 0.5 microg/ml and complete inhibition at 1-5 microg/ml. The inhibitory actions of 15-d-delta 12,14-PGJ2 on LPS + IFN-gamma-induced inflammatory events are not associated with the inhibition of iNOS enzymatic activity or macrophage cell death, but appear to result from an inhibition of iNOS and IL-1 transcription. In addition, the anti-inflammatory actions of 15-d-delta 12,14-PGJ2 are not limited to peritoneal macrophages, as 15-d-delta 12,14-PGJ2 prevents TNF-alpha + LPS-induced resident islet macrophage expression of IL-1beta and beta-cell expression of iNOS stimulated by the local release of IL-1 in rat islets. 15-d-delta 12,14-PGJ2 appears to be approximately 10-fold more effective at inhibiting resident islet macrophage activation (in response to TNF + LPS) than IL-1-induced nitrite production by beta-cells. Two mechanisms appear to be associated with the antiinflammatory actions of both 15-d-delta 12,14-PGJ2 and troglitazone: 1) the direct inhibition of cytokine- and endotoxin-stimulated iNOS and IL-1 transcription; and 2) the inhibition of IL-1 signaling, an event associated with PPAR-gamma agonist-induced activation of the heat shock response (as assayed by heat shock protein 70 expression). These findings indicate that the PPAR-gamma agonists, troglitazone and the J series of prostaglandins, are potent anti-inflammatory agents that prevent cytokine- and endotoxin-stimulated activation of peripheral and resident tissue macrophages and cytokine-induced iNOS expression by beta-cells by the inhibition of transcriptional activation and induction of the heat shock response.

Animals↗
PubMed2002

Troglitazone downregulates delta-6 desaturase gene expression in human skeletal muscle cell cultures.

Delta-6 Desaturase, one of the rate-limiting enzymes, catalyzes the conversion of linoleic acid (C18:2 omega6) into gamma-linolenic acid (C18:3 omega6), arachidonic acid (C20:4 omega6), and further metabolites. Recently, it has been shown that human Delta-6 desaturase is expressed not only in liver but in a variety of human tissues, including muscle. Skeletal muscle is a major site of insulin action, and insulin sensitivity may be related to the fatty acid composition of muscle lipids. We examined the effects of troglitazone on the regulation of Delta-6 desaturase gene expression in human muscle cell cultures obtained from muscle biopsies (n = 15). Delta-6 Desaturase mRNA and peroxisome proliferator-activated receptor gamma2 (PPARgamma2) mRNA were quantified by two-step RT-PCR, and the activity of the Delta-6 desaturase enzyme was estimated by gas chromatographic analysis of the omega 6-C18:3/C18:2 fatty acids ratio. In cells treated with 11.5 micromol troglitazone for 4 days, PPARgamma2 mRNA levels were significantly increased (301.0 +/- 51.5%, P < 0.05) and Delta-6 desaturase mRNA levels were significantly decreased (41.7 +/- 5.9%, P < 0.0005) compared with the untreated controls. In accordance with the decrease of Delta-6 desaturase mRNA, there was a significant decrease in the omega6-C18:3/C18:2 ratio down to 47.4 +/- 7.5% in cholesterol esters, 54.2 +/- 7.4% in phospholipids, 56.7 +/- 6.5% in nonesterified fatty acids, and 67.7 +/- 5.9% in triglycerides. The troglitazone-induced decrease in Delta-6 desaturase mRNA is associated with a change in the unsaturated fatty acid composition of the muscle cells. These results add new aspects to the known thiazolidinedione effects on lipid metabolism.

Adult↗
PubMed2000

[Cardiovascular effects of the thiazolidinedione troglitazone].

Troglitazone, a newly introduced insulin sensitizer, has been implicated in prevention and treatment of atherosclerotic cardiovascular disease especially associated with type 2 diabetes mellitus and insulin resistance. Beneficial effects of troglitazone on multiple risk factor syndrome have been reported in terms of blood pressure lowering effect and ameliorations of dyslipidemia and hyperinsulinemia. Moreover, in vitro and in vivo studies have shown vasodilating and antiatherogenic effects as well as cardioprotective action of this compound. Thus, troglitazone may have potential to prevent and delay diabetic heart disease and large vessel complications.

Animals↗
PubMed2004

[Peroxisome proliferator-actived receptor-gamma ligand troglitazone induces apoptosis in renal cell carcinoma].

UNLABELLED: OBJECTIVE To investigate the expression of peroxisome proliferator-actived receptor-gamma (PPAR-gamma)and the inducement of apoptosis by PPAR-gamma ligand in renal cell carcinoma(RCC)-derived cell lines. METHODS: RT-PCR and Western blot analysis were performed to determined the expression of PPAR-gamma mRNA and protein in two RCC derived cell lines(786-O and A498) and two normal kidney(NK)-derived cell lines(HK-2 and HMCC). Two RCC cell lines were treated with 50 micromol/L troglitazoned for and evaluated for the effects of antidiabetic thiazolidinediones (TZDs) on the cells apoptosis by fluorescence microscopy and DNA ladder assay. The mutative expressions of Bcl-2 and Bax before and after TZDs treatment were also performed by western blot analysis. RESULTS: The expression of PPAR-gamma was observed to be stronger in 786-O and A498 cells than in HK-2 and HMCC cells by RT- PCR and Western blot analysis. Treated with 50 micromol/L troglitazone (for 48 h) it induced typical apoatosis in 786-O and A498 cells. After treatment, a decrease in Bcl-2 expression in RCC cells was observed by Western blot analysis,and the expression of Bax,however,was up-regulated. CONCLUSION: The results reveal that troglitazone has the tumor-suppressive effect on RCC cells. High-affinity PPAR-gamma ligands (TZDs) may be the candidates for a novel approach to the treatment of this refractory neoplasm.

Antineoplastic Agents↗