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See detailPioglitazone reverses down-regulation of cardiac PPARgamma expression in Zucker diabetic fatty rats.
Pelzer, Theo; Jazbutyte, Virginija; Arias-Loza, Paula Anahi et al

in Biochemical and biophysical research communications (2005), 329(2), 726-32

Peroxisome proliferator-activated receptor-gamma (PPARgamma) plays a critical role in peripheral glucose homeostasis and energy metabolism, and inhibits cardiac hypertrophy in non-diabetic animal models ... [more ▼]

Peroxisome proliferator-activated receptor-gamma (PPARgamma) plays a critical role in peripheral glucose homeostasis and energy metabolism, and inhibits cardiac hypertrophy in non-diabetic animal models. The functional role of PPARgamma in the diabetic heart, however, is not fully understood. Therefore, we analyzed cardiac gene expression, metabolic control, and cardiac glucose uptake in male Zucker diabetic fatty rats (ZDF fa/fa) and lean ZDF rats (+/+) treated with the high affinity PPARgamma agonist pioglitazone or placebo from 12 to 24 weeks of age. Hyperglycemia, hyperinsulinemia, and hypertriglyceridemia as well as lower cardiac PPARgamma, glucose transporter-4 and alpha-myosin heavy chain expression levels were detected in diabetic ZDF rats compared to lean animals. Pioglitazone increased body weight and improved metabolic control, cardiac PPARgamma, glut-4, and alpha-MHC expression levels in diabetic ZDF rats. Cardiac [(18)F]fluorodeoxyglucose uptake was not detectable by micro-PET studies in untreated and pioglitazone treated ZDF fa/fa rats but was observed after administration of insulin to pioglitazone treated ZDF fa/fa rats. PPARgamma agonists favorably affect cardiac gene expression in type-2 diabetic rats via activation and up-regulation of cardiac PPARgamma expression whereas improvement of impaired cardiac glucose uptake in advanced type-2 diabetes requires co-administration of insulin. [less ▲]

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See detailThe estrogen receptor-alpha agonist 16alpha-LE2 inhibits cardiac hypertrophy and improves hemodynamic function in estrogen-deficient spontaneously hypertensive rats.
Pelzer, Theo; Jazbutyte, Virginija; Hu, Kai et al

in Cardiovascular research (2005), 67(4), 604-12

OBJECTIVE: Cardiac mass increases with age and with declining estradiol serum levels in postmenopausal women. Although the non-selective estrogen receptor-alpha and -beta agonist 17beta-estradiol ... [more ▼]

OBJECTIVE: Cardiac mass increases with age and with declining estradiol serum levels in postmenopausal women. Although the non-selective estrogen receptor-alpha and -beta agonist 17beta-estradiol attenuates cardiac hypertrophy in animal models and in observational studies, it remains unknown whether activation of a specific estrogen receptor subtype (ERalpha or ERbeta) might give similar or divergent results. Therefore, we analyzed myocardial hypertrophy as well as cardiac function and gene expression in ovariectomized, spontaneously hypertensive rats (SHR) treated with the subtype-selective ERalpha agonist 16alpha-LE2 or 17beta-estradiol. METHODS AND RESULTS: Long-term administration of 16alpha-LE2 or 17beta-estradiol did not affect elevated blood pressure, but both agonists efficiently attenuated cardiac hypertrophy and increased cardiac output, left ventricular stroke volume, papillary muscle strip contractility, and cardiac alpha-myosin heavy chain expression. The observed effects of E2 and 16alpha-LE2 were abrogated by the ER antagonist ZM-182780. Improved left ventricular function upon 16alpha-LE2 treatment was also observed in cardiac MRI studies. In contrast to estradiol and 16alpha-LE2, tamoxifen inhibited cardiac hypertrophy but failed to increase alpha-myosin heavy chain expression and cardiac output. CONCLUSIONS: These results support the hypothesis that activation of ERalpha favorably affects cardiac hypertrophy, myocardial contractility, and gene expression in ovariectomized SHR. Further studies are required to determine whether activation ERbeta mediates redundant or divergent effects. [less ▲]

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