Endocrine Abstracts

Resistin, a new 12.5 kDa cysteine-rich protein, which is specifically secreted by adipocytes and describe as a potential link between obesity and insulin resistance. Recently, resistin and PPARs receptors was found in reproductive tissue such as ovary and it was found that resistin modulate ovarian follicle function. Additionally, thiazolidinediones, such as rosiglitazone, a synthetic agonist of PPAR-γ down-regulated resistin expression in rodents. The aim of the study was to analyze i) basal resistin and PPAR gene and protein expression and ii) effect of resistin and rosiglitazone on PPAR-γ gene and protein expression. Porcine ovaries were collected from normal oestrus cycling crossbred gilts (6–8 months of age; Large White and Polish Landrace) at a local abattoir. Small (2–4 mm; SFs, n=6), medium (4–6 mm; MFs, n=6) and large (8–12 mm; LFs, n=6) follicles collected at days 4–6, 10–12, and 16–18 respectively. Ovarian follicles were cultured in the presence or absence of resistin (at doses 0.1, 1 and 10 ng/ml) or rosiglitazone (at doses 25 and 50 μM, diluted in DMSO) in M199 medium. After 24 h, conditioned culture media were removed but ovarian follicles were homogenized to measurement expression of PPAR-γ receptor by immunoblot and real-time PCR in all follicles. Additionally, basal resistin and PPAR gene and protein expression were also determined. Statistical analyses were performed using GraphPad Prism 5 software. Data were analyzed using a one-way analysis of variance (ANOVA) test, followed by Tukey’s honestly significant difference (HSD) test. We demonstrated that basal PPAR was increased with maximum expression in LFs but resistin expression was unchanged in ovarian follicles. Moreover, both resistin and rosiglitazone increased PPAR-γ expression. In conclusion, our study provides the novel evidence interaction among resistin and PPAR-γ in the pig ovary and suggest involvement of this receptor in the control of key ovary function.