p53 is a hormonally regulated target gene. Animals were treated by the experimental regime described in Materials and Methods. The no. 4 abdominal gland was excised either 3 days after E/P treatment, on day 97, or 3 days after carcinogen administration. Tissues were fixed in 10% neutral buffered formalin and stained for p53. (A and B) AMV, 3 days E/P; (C and D) AMV 97 days; (E and F) AMV, 3 days MNU; (G and H) E/P-treated, 3 days E/P; (I and J) E/P-treated, 97 days; (K and L) E/P-treated, 3 days MNU.