异体垂体移植大鼠E2诱致催乳素瘤的实验研究

目的 探讨催乳素瘤的发病机理,验证其原发于腺垂体的假说。方法 应用雄性Ｓ．Ｄ大鼠进行异体垂体移植,并通过背部埋植１７－β－雌二醇（Ｅ２）药泵,观察Ｅ２对大鼠原位垂体,异体移植于肾囊的垂体及血浆催乳素（ｐｒｏｌａｃｔｉｎ,ＰＲＬ）水平的影响。并利用上述垂体细胞原代培养及原位杂交组化方法,研究经Ｅ２作用１２０ｄ后的原位及移植垂体细胞中ＰＲＬ基因表达水平的改变。结果 经Ｅ２作用６０ｄ及１２０ｄ后,大鼠体

E2-induced prolactin-secreting tumor of heteroplasty pituitary in renal capsule of the rats

OBJECTIVE: A prolactin-producing tumor induced by 17-beta-estradiol (E2) in isotransplanted pituitaries under renal capsules of SD rats were studied. METHODS: Male SD rats (30 days old) were transplanted with an isologaus pituitary under renal capsule and treated with subcutaneous implantation of an empty or E2-laden silastic capsule. RESULTS: After treated with E2 for 60 days and 120 days, both the eutopic and ectopic pituitaries were more than three times heavier than those from control rats, accompanied by hyperprolactinemia, and the body weight of rats decreased significantly. The effects of E2 on the weight of eutopic pituitary and the concentration of plasma PRL were time-dependent. In situ hybridization was employed to measure the levels of PRL mRNA expression in cells from the eutopic and ectopic pituitaries 120 days after treatment of E2. The PRL mRNA contents in both the eutopic and ectopic pituitary cells were much greater than those in untreated pituitary cells. But PRL mRNA levels showed no significant difference between the eutopic and ectopic pituitary cells. CONCLUSIONS: Our previous data has shown that prolactinomas can be induced by chronic treatment of E2 in eutopic pituitaries of SD rats. In present study it appeared that E2 exerted similar effect on the ectopic pituitaries which were distant from the hypothalamus. Our results also demonstrated that E2 could promote the PRL gene expression in both the eutopic and ectopic pituitary cells, and there was no significant difference between them. Our data suggested the possibility of PRL-producing pituitary tumors could originate from anterior pituitary.