On the other hand, in prolactinomas harbored by lacDrd2KO female mice, not only Notch1 and Notch3 mRNA levels but also NOTCH2-3 membrane and NOTCH1 active domains were highly expressed in knockout mice compared to their control counterparts, the Drd2loxP/loxP mice. This evidence concerns the gene NOTCH1 and prolactin-producing pituitary gland adenoma.