The Relationship Between the Effects of of Sulpride, SCH23390, and L-dopa on the Relative Gene Expression of neuropeptide Y and kisspeptin in Polycystic Ovary Syndrome (PCOS) Rat Models

Polycystic ovary syndrome (PCOS) is associated with decreased dopamine release and increased secretion of GnRH, kisspeptin and neuropeptide Y (NPY).  In the present study, the effects of L-dopa and dopamine receptor antagonists were investigated on the expression of KiSS1 and NPY genes in PCOS rats hypothalamus. Following the induction of PCOS by Estradiol Valerate inejction, 25 PCOS rats assigend to 5 groups received saline, L-dopa (100mg/kg), simultaneous injection of SCH23390 (1 mg/kg) and L-dopa (100 mg/kg),  simultaneous injection of sulpride (10 mg/kg) and L-dopa (100 mg/kg), and simultaneous injection of SCH23390 (1 mg/kg), sulpride(10 mg/kg) and L-dopa (100 mg/kg) respectively. Five intact rats received saline. Hypothalamus samples were isolated and frozen. The relative expressions of KiSS1 and NPY were determined by real- time-PCR. Data analysis was done by one- way ANOVA and post hoc Tukey test. The mean relative expression of KiSS1 and NPY significantly increased in PCOS group compared to the healthy rat group (p = 0.009 and p = 0.001, respectively). L-dopa injection caused a significant decrease in the mean relative expression of KiSS1 and NPY compared to the PCOS group (p = 0.001 and p = 0.001 respectively). Simultaneous injections of SCH23390 and sulpride supressed the inhibitory effects of L-dopa on KiSS1 gene expression compared to L-dopa group exerting synergistic effects (p = 0.045).  Dopaminergic signaling pathway may play a role in the decrease of GnRH/LH secretion in PCOS rats by inhibiting the kisspeptin and NPY neuronal activity.