Penile apoptosis in association with p53 under lack of testosterone.

It is known that testosterone deficiency induces apoptosis in the prostate and that p53 protein is involved in this apoptosis. Therefore, p53 protein may also be involved in apoptosis induction in a testosterone-deficient state in the penis. In this study, we investigated whether castration and chemical castration induce apoptosis at penile tissue in rats, and whether p53 protein is involved in this apoptosis. Male SD rats aged 8 weeks were divided into four groups: 1) the Control group; 2) the Castration group; 3) the Estrogen group, in which rats received betaestradiol 17-(beta-D-glucuronide) injection of 500 microg/body/day; and 4) the LH-RH group, in which rats received LH-RH analogue (leuprorelin acetate) injection of 2 mg/kg. The rats were sacrificed after treatment on days 1, 3, 5, 14, and 28 by cervical dislocation. Apoptotic cells and p53 protein-positive cells were observed on the 5th day after treatment and thereafter in all castration, estrogen, and LH-RH groups. These findings showed that both castration and chemical castration induced p53 protein in vascular endothelial cells in the corpus cavernosus during the process of losing testosterone. It was also suggested that in such states, apoptosis is induced in vascular endotherial cells in the corpus cavernosus.