Relation between visfatin, insulin resistance and androgen levels in women with polycystic ovary syndrome with and without clinical hyperandrogenism running title: visfatin and polycystic ovary syndrome

Background: Polycyhc ovary syndrome PCOS is the most common cause of infertility due to anovulation. PCOS patients are at a higher risk of developing type 2 diabetes mellitus and cardiovascular disease. Controversial results were reported regarding levels of visfatin among PCOS patients

Objectives: the aim of the present study was to investigate serum visfatin, testosterone and insulin resistance and the association between these parameters in PCOS patients with and without clinical hyperandrogenism

Subjects and Methods: A total of forty PCOS patients and twenty age BMI-matched overweight healthy control subjects were enrolled in this study. PCOS patients were further divided according to the presence or the absence of clinical hyperandrogenism. Serum visfatin, testosterone, insulin and glucose were measured and the homeostasis model assessment of insulin resistance [HOMA-IR] was calculated

Results: PCOS patients had higher levels of visfatin, testosterone and HOMA-IR compared with the controls. Positive correlation was seen between insulin and testosterone in PCOS patients. PCOS patients with clinical hyperandrogenism had relatively higher levels of visfatin, testosterone and HOMA-IR compared with those without clinical hyperandrogenism. Furthermore, serum visfatin positively correlated with serum insulin and testosterone in PCOS patients with clinical hyperandrogenism, but not in those without clinical hvperandrogenism

Conclusion: There are strong relationships between visfatin and hyperinsulinemia, and hyperandrogenism. Further investigation is needed to elucidate the molecular mechanism behind these relationships

Post-natal developmental changes in the electrophysiological properties of rabbit atrioventricular node Running title: elcctrQphysiological differences in the developing atrioventricular node

There are important post-natal developmental changes in the heart: as compared to the in the adult, the intrinsic heart rate is slower, the sinoatrial node [SAN] and ventricular action potentials are longer. However, little is known about post-natal developmental changes in the electrophysiological properties of the atrioventricular node [AVN]. The aim of this study was to investigate the differences in the electrophysiological properties of the AVN in the neonate [2-7 days of age] and adult [6 months of age] New Zealand White rabbits. Extracellular potential was recorded from isolated spontaneously beating AVN preparations from neonate and adult rabbits under control conditions and after the application of ion channel blocker s. A VN cycle length was significantly longer in adult as compared to neonate. 2 mM cesium Cs, an If blocker] and 100 nM tetrodotoxin [TTX, a TTX-sensitive neuronal I[na] blocker] significantly increased adult AVN cycle length with almost no effect on neonatal AVN cycle length. In contrast, 5 mM 4-aminopyridine [4-AP, a blocker of I[10]] significantly reduced adult AVN cycle length. Moreover, 2 mM C.v increased while 100 nM TTX almost didn't change and 5 mM 4-AP decreased the difference in cycle length between the neonate and adult rabbit. It can be concluded that there is post-ntitul developmental differences in the electrophysiological properties of the AVN that could speculate differences in the underlying currents and that 4-AP-sensitive currents may be partly responsible for the difference in cycle length between the neonate and adult rabbit