Effects of Dopamine and L-dopa on Ghrelin Gene Expresion in the Hypothalamus and Ovary in a Polycystic Ovarian Syndrome Rat Model

Background and Aim: In healthy people, dopamine stimulates ghrelin secretion. The level of dopamine release and ghrelin is lower in the patients with polycystic ovary syndrome (PCOS). In the present study,we investigated the effects of doplamin and L-dopa on relative gene expression of ghrelin in PCOS model rats. Materials and Methods: In the first step of the study, PCOS was induced in 25 female Wistar rat (Rattus norvegicus) by injection of estradiol. Then, the rats received saline, dopamine (5µg), L-dopa (5µg) or simultaneous injections of sulpride (10µg/kg), SCH23390 hydrochloride (10µg/kg) and dopamine or L-dopa respectively via third cerebral ventricular. In the second part of the study, 15 PCOS rats received saline L-dopa (100mg/kg) or dopamine (50mg/kg) intraperitoneally. Hypothalamic and ovarian samples were dissected. Mean relative ghrelin gene expression was determined by real- time-PCR method. Results: Mean relative gene expression of ghrelin significantly decreased in the hypothalamus and ovary of the rats with PCOS compared to those in the intact rats. Intraventricular injection of dopamine or L-dopa significantly increased the hypothalamic ghrelin gene expression in comparison to that in the rats in the PCOS group. Dopamine or L-dopa did not significantly increase the gene expression of ovarian ghrelin in comparison to that in PCOS group. Injections of sulpride and SCH23390 significantly blocked the stimulatory effects of dopamine or L-dopa on the ghrelin gene expression in hypothalamus compared to those in the dopamine or L-dopa group. Conclusion: The dopaminergic pathway may be involved in increasing ghrelin gene expresion extremely via hypothamic level in PCOS condition.