Effect of low-intensity pulsed ultrasound on prepubertal rat testis.

The testes of prepubertal male rats (N = 12) aged 21 days were stimulated with low-intensity pulsed ultrasound (1.5-MHz frequency, 1-KHz repetition pulse rate, 200-microseconds pulse width, 30-V peak-to-peak amplitude and 20-mW/cm2 intensity) applied to the skin for 20 min/day for 7 days. Control rats (N = 8) were manipulated in the same manner but not submitted to ultrasound. Ultrasound stimulation promoted a significant increase in plasma testosterone (62%) leading to a significant increase in seminal vesicle relative weight (35%) as well as an increase in the fructose (92%) and DNA (200%) contents of the gland. No differences were detected between ultrasound-treated and control animals in terms of body weight and the relative weights of testis, cauda epididymidis, testis DNA and mitosis.