The influence of dihydrotestosterone propionate (DHT) and estradiol (E) on prostate growth and micturition was evaluated. Complete studies were carried out on 49 Sprague-Dawley rats over a 14day period. Rats were divided into three groups: (1) controls, (2) DHT, and (3) DHT + E. All groups were injected daily with 0.1 ml of sesame oil, together with 1.25 mgkg of DHT for group 2 and 1.25 DHT + 0.125 mgkg E for group 3. Physiological measurements of micturition were done weekly by subcutaneously administering a fluid loading dose consisting of 10 mgkg furosemide + 5 ml saline. Parameters of micturition frequency, volume, and prostate weight were calculated. Prostate weight values for controls were 0.89 * 0.06 g while those treated with DHT increased significantly to 1.26 * 0.10 g (P < 0.05) and those treated with DHT + E also increased sigruficantly to 1.24 f 0.09 g (P < 0.05). There was no significant difference in prostate weight between the DHT and DHT + E groups. Analysis of micturition data shows that the mean volume voided per micturition decreases in both the DHT and DHT + E treated rats. At between 7 and 14 days of DHT and DHT + E treatment, rats micturated at sigruhcantly reduced mean volumes.
The lowest mean volume per micturition was detected on the 14th day of DHT treatment, showing a sigxuficant reduction from control values of 3.05 f 0.27 to 1.68 f 0.05 ml. The corresponding value of the mean micturated volume in the DHT + E groups was 1.86 2 0.31 ml. Control values for frequency of micturition was 3.25 2 0.52/hr, while for rats treated with DHT it was 3.62 f 0.38hr and for DHT + E it was 4.0 0.54/hr. Evidence is provided to demonstrate that 14 day DHT, and particularly DHT + E, stimulation produces significant alterations in prostate weight and micturition characteristics of unanesthetized rats. On the basis of these observations it is proposed that the hormonally enlarged prostate promotes stimuli to trigger the spinal micturition reflex, thereby producing increased frequency of micturition.