脑内甾体激素受体

甾体激素受体在脑内的生理意义与机理所知尚少,本文应用受体放射分析技术与现代生物化学分析技术(如等电聚焦电泳,超离心技术)对鼠脑与人脑内的糖皮质激素受体(GR)、盐皮质激素受体(MR)、雌激素受体(ER)与孕激素受体(PR)的化学特性、含量检测及其临床意义作了比较系统的研究。尤其侧重在人脑肿瘤中GR,MRER和PR与脑水肿的关系和对肿瘤治疗及预后方面所起的作用。 概括地说,人脑与脑肿瘤中的GR与血管源性脑水肿的治疗和转归有密切关联;根据CT观察,进一步证实血管源性脑水肿主要原因是病变区血管的通透性呈病理性增高。糖皮质激素由于能降低和改善血管通透性,对脑水肿起到积极的治疗作用。颅内肿瘤中GR的多少与治疗因肿瘤引起的血管源性脑水肿的效果成正比。人脑与脑肿瘤,尤其是胶质细胞瘤中的MR推论与缺血性脑水肿的形成与发展有密切联系。而脑膜瘤象乳癌一样,瘤组织中含有ER及PR的阳性率分别为94％与82％;说明脑膜瘤是一种与雌激素关系密切的肿瘤,为今后对这类肿瘤的内分泌治疗开辟了道路。

Steroid Hormone Receptors in Brain

The concentration of glucocorticoid, mineralocorticoid,estrogen and progestin receptors has been determined in brain and in various brain tumors. The appearance of various intracranial neoplasms has been examined with computed tomography (CT) and related to the effect of steroid treatment and to receptor levels.The results can be summarized as follows: 1 . Glucocorticoid Receptor in Brain1 ) The glucocorticoid receptor proteins in cytosol from human and rat brain are similar both with regard to protein structure and hormone specificity. 2 ) The average concentration of glucocortic'oid receptor in various intracranial les-ions was as follows; cerebral metastases > meningiomas > acoustic neuromas > gliomas>peritumoral brain tissue>contused brain tissue. The clinical response to dexamethasone in brain edema associated with various intracranial lesions is to some extent parallel to the GR concentration in these lesions.3 ) The study on the relationship between CT findings and glucocorticoid receptorconcentrations in various intracranial tumors showed that some correlation existed between the glucocorticoid receptor level and CT contrast enhancement. This indicates that glucocorticoid receptor interaction is of importance in the regulation of the vascular permeability of tumors.4 ) The effect of dexamethasone treatment on brain edema was evaluated by CT in14 patients with various intracranial tumors.The degree of reduction of edema volume (cerebral metastases>gliomas>meningiomas)following steroid treatment paralleled the clinical response of dexamethasone. Ⅱ. Mineralocorticoid Receptor in Brain1 ) Rat kidney and rat hippocampus contain a mineralocorticoid receptor with similar properties in these two tissues which can be distinctly separated from the glucocorticoid receptor. 2 ) The order of tumor types with respect to average concentration of mineralocorticoid receptor was gliomas>neuromas>metastases >meningiomas. Glial cellshave a high concentration of intranuclear sodium, and it was found that gliomasalso have high levels of mineralocorticoid receptors. This indicates that the mineralocorticoid receptor may play a role in the cause and process of cytotoxic brain edema.Ⅲ.Estrogen and progestin Recentors in BrainFifteen of sixteen (94%) and nine of eleven (82%) meningiomas had detectable amounts of estrogen and progestin receptors, respectively. Except for one case of acoustic neuroma, other types of intracranial tumors did not contain detectable amounts of estrogen receptors.These results indicate that the sex steroid receptor profile of meningiomas is unique among intracranial neoplasms. The findings give further support to the view that selective endocrine therapy can be considered as an alternative treatment in case of meningioma,especially in poor-risk patients. In conclusion the study has extended the knowledge of steroid hormone receptors in brain tissue and neoplasms and indicates that glucocorticoid and mineralocorticoid receptors may play roles in the cause of and treatment of vasogenic edema and cytotoxic edema, respectively, whereas meningioma probably could be subjected to selective endocrine therapy.