ABSTRACT
Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, is metabolized in the liver by dimethylarginine dimethylaminohydrolase (DDAH). We aimed to investigate the effect of rosiglitazone, a peroxysome proliferator-activated receptor-gamma (PPAR-γ) agonist, on ADMA metabolism in acute liver injury. Male Sprague Dawley rats were injected thioacetamide (TAA; 500mgkg(-1)) intraperitoneally in order to induce acute liver injury. ADMA, SDMA and arginine levels were determined in plasma by the HPLC. Liver DDAH activity and malondialdehyde (MDA) levels were measured by spectrophotometric procedures. TAA injection caused marked increases in ALT and AST activities. Plasma ADMA levels were increased, while arginine levels and arginine/ADMA ratio were decreased. Liver DDAH activity was significantly diminished and MDA levels were elevated. In another group of animals which were treated with a PPAR-γ agonist (rosiglitazone, 5mgkg(-1)) daily via gastric intubation for a week prior to TAA injection, significant recoveries in DDAH activity and antioxidant status were observed when compared with solely TAA-injected animals. Rosiglitazone pretreatment improved the plasma arginine/ADMA ratio. Our findings indicated that PPAR-γ agonist rosiglitazone beneficially influenced hepatic metabolism of ADMA in TAA-induced acute liver damage.
ABSTRACT
OBJECTIVE: A high dose of prolonged gonadotropins can yield higher numbers of oocytes and embryos. The high dose or prolonged regimens can be associated with ovarian hyperstimulation syndrome (OHSS), multiple gestations, emotional stress, economical burden and treatment dropout. In mild stimulation lower doses and shorter duration times of gonadotropin are used in contrast to the conventional long stimulation protocol in IVF. It has been proposed that supraphysiologic levels of hormones may adversely affect endometrium and oocyte/embryo. Also it has been proposed that oxidative stress (OS) may alter ovarian hormone dynamics and could be further affected by additional exogenous hormonal stimulation. Therefore our aim was to compare follicular fluid total antioxidant capacity (TAC) in antagonist mild and long agonist stimulations. MATERIALS AND METHODS: Forty patients received antagonist mild stimulation, starting on the 5th day of their cycle and forty patients received long agonist treatment. Seventy-five patients undergoing their first IVF cycle were included in the final analysis. Follicular fluid (FF) samples were analyzed for estradiol (E2), antimullerian hormone (AMH) and TAC. RESULTS: FF-Total antioxidant capacity (TAC) levels were higher in the long agonist group as opposed to the antagonist group [1.07 ± 0.04 mmol Trolox equivalent/L vs 1 ± 0.13 mmol Trolox equivalent/L] (Fig. 1). Pregnancy rates were not significantly different between the two treatments. The FF-TAC levels were not different among infertility etiologies (Fig. 3). FF-TAC levels did not have a direct correlation with pregnancy but a positive correlation with the total gonadotropin dose was observed. CONCLUSION: Patients with good ovarian reserves and under the age of 35 effectively responded to mild stimulation treatment. Using lower amounts of gonadotropin, yielded less FF-TAC levels in patients who underwent antagonist mild protocol. In patients under the age of 35, antagonist mild stimulation is a patient friendly and effective procedure when undergoing their first IVF cycle.