Effects of targeted deletion of Rb1 in pituitary IL of p27T187A KI mice. a. IL morphology, PCNA expression, Ki67 and TUNEL labeling, and p27 expression were examined at the indicated ages, with quantification of Ki67 and TUNEL labeling presented in b and c, respectively. p values are by t test. Error bars are s.d. d. IL morphology and PCNA expression after Rb1 deletion in p27T187A/+ mice at 7 and 11 weeks of age. Scale bar, 200 μm.