Studies on the regulatory effect of Peony-Glycyrrhiza Decoction on prolactin hyperactivity and underlying mechanism in hyperprolactinemia rat model.

Clinical trials have demonstrated the beneficial effects of Peony-Glycyrrhiza Decoction (PGD) in alleviating antipsychotic-induced hyperprolactinemia (hyperPRL) in schizophrenic patients. In previous experiment, PGD suppressed prolactin (PRL) level in MMQ cells, involving modulating the expression of D 2 receptor (DRD 2 ) and dopamine transporter (DAT). In the present study, hyperPRL female rat model induced by dopamine blocker metoclopramide (MCP) was applied to further confirm the anti-hyperpPRL activity of PGD and underlying mechanism. In MCP-induced hyperPRL rats, the elevated serum PRL level was significantly suppressed by either PGD (2.5–10 g/kg) or bromocriptine (BMT) (0.6 mg/kg) administration for 14 days. However, in MCP-induced rats, only PGD restored the under-expressed serum progesterone (P) to control level. Both PGD and BMT administration restore the under-expression of DRD 2 , DAT and TH resulted from MCP in pituitary gland and hypothalamus. Compared to untreated group, hyperPRL animals had a marked reduction on DRD 2 and DAT expression in the arcuate nucleus. PGD (10 g/kg) and BMT (0.6 mg/kg) treatment significant reversed the expression of DRD 2 and DAT. Collectively, the anti-hyperPRL activity of PGD associates with the modulation of dopaminergic neuronal system and the restoration of serum progesterone level. Our finding supports PGD as an effective agent against hyperPRL. [ABSTRACT FROM AUTHOR]