We examined alterations in the expression of tumorigenesis-related genes in the pituitary gland of rats exposed to electromagnetic pulses (EMP).The global gene expression profiles of the pituitary gland in EMP-exposed and control groups were detected by cDNA microarray analysis. We then validated and further investigated the reduced expression of two tumorigenesis-related genes, Pten, and Jund, by assessing their mRNA and protein expression by quantitative real-time-PCR, western blotting, and immunohistochemistry in the pituitary gland of rats 6 months after exposure to EMP.EMP exposure induced genome-wide gene expression changes in the rat pituitary gland. There was decreased expression of the Pten and Jund mRNAs and proteins in EMP-exposed rats compared with in unexposed control animals.EMP exposure alters the expression of tumorigenesis-related genes in the pituitary gland. These tumorigenesis-related genes are potentially involved in the development of pituitary gland tumors in rats.