ABSTRACT
PURPOSE: Androgen plays an important role during penile development and is essential for a normal libido in the male, but its role in the regulation of the androgen receptor and maintenance of erectile response has been controversial. We investigated the effect of androgen on apoptosis, proliferation of the penile erectile tissue and androgen receptor after castration and temporary androgen replacement. MATERIALS AND METHODS: Male adult Sprague Dawley rats were divided into three groups; sham-operation, castration, and androgen replacement after castration. Androgens (testosterone, DHT) were administrated for 7 days at week 1, 2, 3, and 4 after castration. The weight of whole body and corpus cavernosum and serum testosterone concentration were measured. Androgen receptor expression, percentage of proliferating cells incorporating Ki-67(proliferative index) and percentage of apoptotic cells assessed by morphological analysis(apoptotic index, TUNEL) were analyzed in the penile erectile tissue. RESULTS: Castration induced a significant decrease in serum testosterone concentration from day 1 and a progressive decrease in the corpus cavernosal weight from day 14. Androgen receptor expression decreased after androgen depletion and was restored with androgen replacement. The proliferative and apoptotic index varied as follows after castration and androgen replacement: a significant increase was noted for apoptotic index with a decrease in the proliferative index and androgen receptor expression after castration. Replacement of testosterone propionate and DHT after castration decreased the apoptotic index with an increase in the proliferative index and the expression rate of androgen receptor. CONCLUSIONS: The penile erectile tissue of the adult rat was affected by the androgen milieu via the androgen receptor as seen by either cellular apoptosis or proliferation. Therefore, androgens such as testosterone and DHT play a direct role in the erectile function of the rat at the level of the penile erectile tissue.
Subject(s)
Adult , Animals , Humans , Male , Rats , Androgens , Apoptosis , Castration , Libido , Rats, Sprague-Dawley , Receptors, Androgen , Testosterone , Testosterone PropionateABSTRACT
Testosterone is required for the development and maintenance of the male accessory sex organs and their normal function. And it was reported that castration affect cells in the adult male rat accessory sex glands by induction of programmed cell death (apoptosis). So, in this study, the authors made an experiment to evaluate the effect of testosterone in the maure male rat penis and accessory sex glands following castration. Also, we utilized actinomycin D, a potent inhibitor of messenger and ribosomal RNA synthesis, in the experiment herein to assess the significance of regression process in the glands. Following are the changes in the serum testosterone level, the weight of the penis, ventral prostate and seminal vesicles and apoptosis occurrence of the control (castration, castration normal saline) and experimental (castration AD25, castration AD50) group of mature rats. 1. After castration, the control group and the experimental group showed decreased level of serum testosterone. 2. In the both groups, the weight of the penis, ventral prostate and seminal vesicles decreased gradually. 3. Compared to the control group, the castration AD25 did not show the inhibition of castration induced regression of penis and ventral prostate. However, castration AD50 showed the inhibition. 4 In the H-E staining and ApoTag in situ staining, the ventral prostate showed the most prominent apoptosis occurrence followed by the seminal vesicles and penis. These results suggest that after castration of the mature rat, due to testosterone deficiency, the weight of penis, ventral prostate and seminal vesicles decreased with the occurrence of apoptosis. Also, actinomycin D 50 micrometer seems to delay the regression process.