Fig. 2.

Effect of DEHP treatment on expression of cell cycle proteins. DEHP treatment from 21 to 90 days of age increased expression of several cell cycle proteins [PCNA and cyclins D₃ (A) and the tumor suppressor protein p53 and cyclin G₁ (B)]. Increased proliferative activity in Leydig cells is therefore due to induction of cell cycle proteins by DEHP treatment. Total RNA was obtained from two separate experiments, and rat ribosomal protein S16 (S16) was used as internal control for PCR amplification. p53, tumor suppressor protein; *, P < 0.05 compared to control. Data are presented as mean ± SEM.