RÉSUMÉ
Objective To observe the effects of malt extract on prolactin expression and morphology of mammary tissue in hyperprolactinemia rats. Methods Metoclopramide hydrochloride was injected subcutaneously to establish hyperprolactinemia model. Sixty rats were divided into normal control group, model control group, bromocriptine group, high-dose, middle-dose and low-dose malt extract groups. Except normal control group, hyperprolactinemia model was established in the other groups. Bromocriptine (0. 389 mg·kg-1 ·d-1 ) was given to bromocriptine group. Malt extract (7. 98, 15. 96 and 31. 92 g·kg-1 ·d-1 ) was administered in low-dose, middle-dose and high-dose malt extract groups. Equal volume of purified water was given to normal control group and model control group. After 30 days of administration, PRL positive cell number of rat hypophysis was counted. RT-PCR was used to measure hypophysis PRL mRNA expression, and morphology of mammary tissues was observed by immunohistochemical method. Results PRL positive cell number was (2. 4±0. 3), (21. 7±0. 8), (3. 8± 0. 5), (4. 5±0. 4), (6. 7±0. 5) and (15. 8±1. 2) in normal control group, model control group, bromocriptine group, high-dose, middle-dose and low-dose malt extract groups. PRL mRNA expression level was (0. 31±0. 02), (1. 58±0. 06), (0. 45± 0. 04), (0. 49±0. 03), (0. 61±0. 04), and (0. 95±0. 09), respectively. As compared with normal control group, hypophysis PRL positive cell number and PRL mRNA expression level of high-dose and middle-dose malt extract group were increased significantly (P<0. 01), and hyperplasia of mammary glands appeared. As compared with model control group, hypophysis PRL positive cell number and PRL mRNA expression level of high-dose and middle-dose malt extract group was decreased significantly (P<0. 01), and hyperplasia of mammary glands was alleviated obviously. Conclusion Malt extract can effectively treat hyperprolactinemia and inhibit hyperplasia of mammary glands through significantly decreasing the expression of hypophysis prolactin in hyperprolactinemia rats.