Estrogen誘発ラットprolactinomaに対するbromocriptineの縮小効果についての基礎的検討
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概要
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Experimental prolactinomas were produced in Wistar rats by weekly injections of 2.5 mg estradiol dipropionate, and the effects of bromocriptine on these prolactinomas were studied by light microscopy, immunohistochemistry, and electron microscopy. Serum concentrations of prolactin and weight of the pituitary gland were markedly increased, more prominently in female rats, even after 6 weeks of weekly injections of estrogen. The prolactin productive cells were diffusely distributed and their population was high. The cytoplasm was mostly chromophobe. Immunohistochemical study of the prolactin showed diffuse staining. Electron microscope study showed that the nuclei were enlarged, containing one or two prominent nucleoli, and the Golgi apparatus and endoplasmic reticulum were strongly developed, while secretory granules were decreased. These morphological findings suggest that estrogen-induced rat prolactinoma simulate human prolactinomas. Discontinuation of estrogen administration for 3 weeks after six weekly injections resulted in a significant lowering of the serum prolactin level, with a tendency to decreased weight of the pituitary gland. Therefore, the effects of 1 mg/kg/day bromocriptine administered intramuscularly for 3 weeks were studied in female rats, without discontinuing estrogen administrations. The weight of the pituitary gland and serum concentration of prolactin were markedly decreased. Light microscopy showed an increase of eosinophilic cells. Immunohistochemical staining of prolactin showed little change. Electron microscope study showed that the Golgi Apparatus and endoplasmic reticulum were markedly reduced and secretory granules were fully increased in the cytoplasm. The mechanism of inhibition of prolactin secretion by bromocriptine is discussed from the viewpoint of the morphological alterations.
- 日本脳神経外科学会の論文
- 1987-06-15