Estrogen-dependent growth of a rat pituitary tumor involves, but does not require, a high level of vascular endothelial growth factor.

Long-term (10-week) treatment of Fischer 344 (F344) rats with the synthetic estrogen diethylstilbestrol (DES) increases the level of vascular endothelial growth factor (VEGF) in the pituitary. This is concurrent with the development of a large tumor of the pituitary of F344 rats. A role for VEGF in estrogen-dependent pituitary tumor growth is also supported by the fact that pituitary VEGF level is not increased by estrogen treatment in rats of the tumor-resistant Brown Norway (BN) strain.