Effects of lactagogue of four total alkaloids of barley malt via dopamine D2 receptor in postpartum hypogalactia rat / 中草药

ABSTRACT

Objective: To explore the regulatory effect of malt alkaloid on prolactin (PRL) secretion in the model rat with postpartum hypogalactia induced by bromocriptine based on dopamine D2 receptor, and determine the active fraction of the malt with galactogogue effect. Methods: The postpartum hypogalactia model was established by intragastric administration of bromocriptine mesylate. After the model was successfully established, all groups were given corresponding drug treatment. The concentration of serum PRL, estradiol (E2) and progesterone (P) in each group was detected by ELISA kits. HE staining was used to observe the pathologic changes of breast tissue. RT-PCR was used to determine the mRNA levels of prolactin receptor (PRLR) and dopamine D2 receptor (DRD2) in pituitary gland of rats. Results: Compared with the control group, the levels of serum PRL, P, and E2 were significantly decreased in the model group as well as the mRNA expression of the pituitary PRL cells. But the mRNA expression of the pituitary DRD2 in the model group was significantly increased compared with the control group. Compared with the model group, the malt total alkaloid significantly increased the volume of mammary lobule and dilated the duct. There was a lot of milk in the duct and acinar in the malt total alkaloid group. Besides, the total alkaloids increased the concentration of serum PRL, P, and E2 and the mRNA expression of the pituitary PRL cells, and decreased the mRNA expression of the pituitary DRD2. Conclusion: The primary the active fraction of malt for galactogogue action is total alkaloids, and its mechanism may be related to promoting PRL secretion, increasing serum PRL receptor level and decreasing the mRNA expression of dopamine D2 receptor.