Résumé
AIM: To observe the changes of metallothionein (MT) in various tissues of mice during hyperhomocysteinemia. METHODS: Intraperitoneal injection of homocysteine into mice induced hyperhomocysteinemia. The contents of tissue MT and malondialdehyde (MDA) in liver, heart and kidney were determined. RESULTS: Compared with control group, tissue MT levels in Hcy-group animals were increased by 210% ( P 0.05),respectively, compared with Hcy alone group. Tissue MDA contents were decreased by 24% ( P
Résumé
AIM: Metallothioneins (MTs) are cysteine-rich metal-binding proteins that exert cytoprotection during metal exposure and oxidative stress. The present study was designed to investigate whether MT can directly protect NTPase on nuclear envelope from damage induced by hydroxyl radical.METHODS: Isolated hepatic nuclei from rat liver were exposed to Fe 2+ /H 2O 2 with or without MT, and the NTPase activity on nuclei was assayed using ATP and GTP as substrate, respectively. RESULTS: Incubation of rat hepatic nuclei with the Fe 2+ /H 2O 2 (in ?mol?L -1 / ?mol?L -1 : 0 1/0 5, 0 5/2 5, 1/5, 5/25) resulted in a concentration-dependent decrease in nuclear NTPase activities ( P0 05 ). In addition, incubation of hepatic nuclei with only MT had no effect on nuclear NTPase activity. CONCLUSION: These data demonstrate that hydroxyl radical generated from Fe 2+ /H 2O 2 might attack nuclear NTPase. MT antagonistically reduces toxicity of Fe 2+ /H 2O 2 system to the NTPase.
Résumé
AIM: To observe the effects of aortal angiotensin Ⅱ (Ang Ⅱ )levels and AngⅡ receptor in the hy- pertensive rat models. METHODS: Intraperinoneal injection of L - Nw - nitro-arginine (L - NNA) into rats induced hypertensive model, the binding of aortal Ang Ⅱ receptor and the contents of aortal tissue Aug Ⅱ and plasma NO2-+ NO3- (NOx) were determined. RESULTS: Compared with the control group, the bind pressure of the rats treated with L - NNA was significantly increased by 142% (P
Résumé
AIM: To elucidate the relations among proadrenomedullin N terminal 20 peptide (PAMP), adrenomedullin(ADM) and angiotensin Ⅱ (Ang Ⅱ). METHODS: Tissue slices of rat aorta were incubated as follows: (I) increasing concentrations of Ang Ⅱ (10-9, 10-8, 10-) mol/L); (Ⅱ) increasing concentrations of PAMP(10-9, 10-8, 10-)mol/L). The tissue and incubation concentrations of PAMP, ADM and Ang Ⅱ were measured by the radioimmunoassay (RIA). RESULTS: The tissue and incubation concentrations of PAMP and ADM were concentration - dependently increased by Ang Ⅱ, but the tissue and incubation concentrations of Ang Ⅱ can not effected by PAMP. CONCLUSION: AngⅡ markedly stimulate the release of ADM and PAMP. It may be one of the factors which regu- late the synthesis and release of ADM and PAMP. The regulation may play an important role in homastasis regulation of cardiovascular system.