Pituitary Isograft Transplantation in Mice

The mouse pituitary isograft is a technique developed to administer persistent hormone stimulation, thereby increasing cellular proliferation in the mammary tissue ( Christov et al., 1993 ). The pituitary isograft procedure was first described in 'Induction of Mammary Cancer in Mice without the Mammary Tumor Agent by Isografts of Hypophyses' by O. Mühlbock and L. M. Boot in 1959 (Muhlbock and Boot, 1959). Since then, the procedure has seen wide use. A pituitary gland is harvested posthumously from a donor mouse and implanted under the renal capsule of the recipient mouse through a small abdominal incision just below the last rib. Once the pituitary gland is implanted, it begins releasing hormones. These secretions increase serum levels of multiple hormones including prolactin, progesterone and 17β-estradiol ( Christov et al., 1993 ). Although the effects of these hormones on cancer cell proliferation, growth, differentiation, and longevity are not well characterized, and, in some cases, controversial, the net effect of a pituitary isograft is to increase the proliferation of murine breast tissue depending upon strain specific characteristics ( Lydon et al., 1999 ). Below is a protocol describing how to perform the pituitary isograft procedure. After many of the steps, a time reference is listed in parentheses. Each reference corresponds to a time point in the embedded video of the procedure. (Video 1) Video 1.Pituitary isograft transplantation in mice. Video portraying pituitary isograft transplantation procedure in donor and recipient mice.