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Hyperthyroid Rats (hyperthyroid + rat)
Selected AbstractsEffect of di(n -butyl) phthalate on testicular oxidative damage and antioxidant enzymes in hyperthyroid ratsENVIRONMENTAL TOXICOLOGY, Issue 3 2007Ena Lee Abstract This study compared the effects of di(n-butyl) phthalate (DBP) on the oxidative damage and antioxidant enzymes activity in testes of hyperthyroid rats. Hyperthyroidism was induced in pubertal male rats by intraperitoneal injection of triiodothyronine (T3, 10 ,g/kg body weight) for 30 days. An oral dose of DBP (750 mg/kg) was administered simultaneously to normal or hyperthyroid (T3) rats over a 30-day period. No changes in body weight were observed in the hyperthyroid groups (T3, T3 + DBP) compared with controls. There were significantly higher serum T3 levels observed in the hyperthyroid rats than in the control, but the serum thyroid stimulating hormone levels were markedly lower in the hyperthyroid rats. DBP significantly decreased the weight of the testes in the normal (DBP) and hyperthyroid (T3 + DBP) groups. The serum testosterone concentrations were significantly lower in only DBP group. DBP significantly increased the 8-hydroxy-2-deoxyguanosine (8-OHdG) level in the testes, whereas the DBP-induced 8-OHdG levels were slightly higher in T3 + DBP group. Superoxide dismutase and glutathione peroxidase activities were significantly higher in the testes of the DBP or T3 + DBP groups. Catalase (CAT) activity was significantly higher in the DBP treatment group, but the T3 + DBP group showed slightly lower DBP-induced CAT activity. The testicular expression of thyroid hormone receptor ,-1 (TR,-1) was significantly higher in the DBP groups, and androgen receptor (AR) expression was not detected in the DBP treatment group. In addition, DBP significantly increased the peroxisome proliferator-activated receptor-r (PPAR-r) levels in the testis. These results suggest that hyperthyroidism can cause a change in the expression level of PPAR-r in testes, and may increase the levels of oxidative damage induced by the metabolic activation of DBP. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 245,255, 2007. [source] Differential effect of hyperthyroidism on rat epididymal glycosidasesINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2001R. R. M. Maran The impact of hyperthyroidism on epididymal glycosidases was studied in albino rats. Hyperthyroidism was induced in Wistar rats aged 30 days by daily injection of T4 (25 ,g/100 g body weight/day intramuscularly) for 30 or 60 days; control rats were injected with vehicle (alkaline saline, pH 7.8). One set of hyperthyroid rats was reverted to euthyroid status by withdrawing T4 treatment after 30 days of hyperthyroidism. To asses the direct effect of thyroid hormone on epididymal hexosaminidases, caput, corpus and cauda tissues were stimulated with 25, 50 or 100 ng/mL T3 for 24 h, after an initial culture of 24 h. The activity of ,-glucosidase decreased in caput, corpus and cauda epididymis of hyperthyroid rats. ,-Galactosidase activity increased in the caput epididymis irrespective of the duration of hyperthyroidism. While a similar decrease occurred in the corpus and cauda epididymis in the 30 day hyperthyroid group, an opposite trend was observed in 60 day hyperthyroid rats. Caput ,- N -acetylglucosaminidase activities increased at both time points, whereas activity decreased in the corpus and cauda in 30 day, but increased in 60 day hyperthyroid rats. Hyperthyroidism consistently increased caput and corpus ,- N -acetylgalactosaminidase activity irrespective of the duration. Cauda epididymal ,- N -acetylgalactosaminidase activity was decreased in 30 day and increased in 60 day hyperthyroid rats. Hyperthyroidism induced changes in caput ,-galactosidase, ,- N -acetylgalactosaminidases, corpus ,-N-acetylglucosaminidase and cauda ,- N -acetylgalactosaminidase which were irreversible while the remaining actvities were brought back to normal when T4 treatment was withdrawn. In vitro studies showed that T3 stimulates epididymal hexosaminidases (,- N -acetylglucosaminidase and ,- N -acetylgalactosaminidase) irrespective of the dose. These data suggest that thyroid hormones have a specific and direct influence on glycosidases in specific regions of the epididymis. [source] Membrane-bound and cytosolic forms of heterotrimeric G proteins in young and adult rat myocardium: Influence of neonatal hypo- and hyperthyroidismJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2001Jiri Novotny Abstract Membrane and cytosolic fractions prepared from ventricular myocardium of young (21-day-old) hypo- or hyperthyroid rats and adult (84-day-old) previously hypo- or hyperthyroid rats were analyzed by immunoblotting with specific anti-G-protein antibodies for the relative content of Gs,, Gi,/Go,, Gq,/G11,, and G,. All tested G protein subunits were present not only in myocardial membranes but were at least partially distributed in the cytosol, except for Go,2, and G11,. Cytosolic forms of the individual G proteins represented about 5,60% of total cellular amounts of these proteins. The long (Gs,-L) isoform of Gs, prevailed over the short (Gs,-S) isoform in both crude myocardial membranes and cytosol. The Gs,-L/Gs,-S ratio in membranes as well as in cytosol increased during maturation due to a substantial increase in Gs,-L. Interestingly, whereas the amount of membrane-bound Gi,/Go, and Gq,/G11, proteins tend to lower during postnatal development, cytosolic forms of these G proteins mostly rise. Neonatal hypothyroidism reduced the amount of myocardial Gs, and increased that of Gi,/Go, proteins. By contrast, neonatal hyperthyroidism increased expression of Gs, and decreased that of Gi, and G11, in young myocardium. Changes in G protein content induced by neonatal hypo- and hyperthyroidism in young rat myocardium were restored in adulthood. Alterations in the membrane-cytosol balance of G protein subunits associated with maturation or induced by altered thyroid status indicate physiological importance of cytosolic forms of these proteins in the rat myocardium. J. Cell. Biochem. 82: 215,224, 2001. © 2001 Wiley-Liss, Inc. [source] Evaluation of the antithyroid, antioxidative and antihyperglycemic activity of scopoletin from Aegle marmelos leaves in hyperthyroid ratsPHYTOTHERAPY RESEARCH, Issue 12 2006Sunanda Panda Abstract Scopoletin (7-hydroxy-6-methoxy coumarin) was isolated from the leaves of Aegle marmelos and evaluated for its potential to regulate hyperthyroidism, lipid peroxidation and hyperglycemia in levo-thyroxine-induced hyperthyroid rats. Scopoletin (1.00 mg/kg, p.o.) administered daily for 7 days to levo-thyroxine-treated animals decreased the levels of serum thyroid hormones and glucose as well as hepatic glucose-6-phosphatase activity, demonstrating its potential to regulate hyperthyroidism and hyperglycemia. Scopoletin also inhibited hepatic lipid peroxidation and increased the activity of antioxidants, superoxide dismutase and catalase. Compared with the standard antithyroid drug, propylthiouracil, scopoletin exhibited a superior therapeutic activity, since unlike propylthiouracil, it also inhibited hepatic lipid peroxidation. These findings indicate that scopoletin has the potential to inhibit thyroid function and hyperglycemia without hepatotoxicity. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||