Influences of L-DOPA and Blocking Dopamine Receptors on Aromatase Gene Expression and Serum Concentration of LH in Rat Model of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is associated with higher plasma levels of androgens, LH/FSH ratio and lower activity of aromatase and dopaminergic signaling pathways. In the present study, the effects of L-DOPA and dopamine receptor antagonists were investigated on aromatase (Cyp19) gene expression and LH concentration in PCOS rat model.

Following PCOS induction by estradiol valerate, The PCOS rats received saline, L-DOPA(100mg/kg) or simultaneous injections of sulpride (10mg/kg)/ SCH23390 (1mg/kg)/ L-DOPA (100mg/kg). Five intact estrous rats were used as a control group. Mean serum LH concentration and aromatase relative gene expression was evaluated by radioimmonoassay and real- time-PCR method respectively.

Mean aromatase mRNA levels significantly decreased in the hypothalamus and ovary of PCOS model rats compared to intact ones. Mean serum LH concentration significantly increased in PCOS group in comparison with intact rats. The L-DOPA significantly increased mean hypothalamic and ovarian aromatase gene expression compared to PCOS rats while it significantly declined serum LH concentration compared to PCOS rats. Dopamine receptor antagonists including sulpiride and SCH23390 blocks the stimulatory or inhibitory effects of L-DOPA on hypothalamic aromatase or serum LH levels respectively. But the sulpride and SCH23390 did not inhibit the stimulatory influences of L-DOPA on ovarian aromatase gene expression.

L-DOPA may be involved in the controling of PCOS condition via decreasing LH secretion and increasing the aromatase gene expresion.