Objective   To explore the changes of endocrinal function and their roles in early stage of prolactinoma after gamma knife radiosurgery (GKRS).   Methods   A total of 27 prolactinoma patients admitted during November 1997 to November 2007 with intact early stage followed-up data were retrospectively reviewed. The dynamical changes for clinical symptoms

and prolactin (PRL) levels during 6 months after GKRS were investigated. The possible clinical roles for the changes were evaluated.   Results   During 6 months after GKRS

the clinical symptoms were improved in 24 patients (89%) and PRL level was decreased in 21 patients (78%) transiently or persistently. The improvement in the symptoms and the reduction in PRL level occurred mostly in the first 2 months after GKS. In Chi-square testing and t  testing showed that there was significant difference between the first or second month and most of the other month after GKRS on improvement rate in the symptoms and PRL levels.   Conclusion   Endocrinal malfunction of prolactinoma can be ameliorated more significantly during the first 2 months after GKS

so this period should be regarded as one of key-stages for pregnancy or contraception in reproductive age females.