Influence of castration on bladder blood flow and function during the rapid phase of androgen deprivation

Abstract

Objective. This study examined the effects of androgen deprivation on bladder blood flow (BBF) and bladder function during the acute phase in castrated rats. Material and methods. Nine-week-old male Wistar rats were divided into six groups as follows: 24 h post-sham-operation (24hPS), no operation (control), 24 h post-castration (24hPC), 48 h post-castration (48hPC), 7 days post-castration (7dPC) and 12 weeks post-castration (12wPC). BBF was measured in the 24hPS, control, 24hPC, 48hPC, 7dPC and 12wPC groups, and prostate blood flow was measured in the control, 24hPC, 48hPC and 7dPC groups using laser Doppler methods. In select groups, BBF was measured using the fluorescent microsphere method. Bladder function was tested in the 24hPS, control, 24hPC and 12wPC groups. The bladder was irrigated with saline and 0.25% acetic acid. Maximum voiding pressure and voiding intervals were measured. Results. BBF significantly increased within 24 h after castration (p < 0.001); these changes did not persist beyond 24 h. However, prostate blood flow decreased significantly within 24 h after castration (p < 0.001). Shortening of the voiding interval upon acetic acid stimulation was significantly suppressed in group 24hPC compared to the control group (p < 0.001). The maximum voiding pressure did not significantly change in the 24hPS, control, 24hPC and 12wPC groups. Conclusions. During the acute phase of androgen deprivation following castration, BBF significantly increased and the bladder became receptive to stimulation. This temporary increase may be because of a decrease in the prostate blood flow, indicating that androgens do not directly affect the BBF.

Key Words::

• androgen deprivation
• acute phase
• bladder blood flow
• fluorescent microsphere method
• laser Doppler method

Acknowledgements

All the animal studies were approved and conducted by the Institutional Laboratory Animal Care and Use Committee of Gunma University School of Medicine. This study was supported in part by a Grant-in-Aid for Young Scientists (B), 2007–2008.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.