The influence of scrotal warming on testicular blood flow and endocrine function in the rat.

The effects of local heating on testicular and epididymal vascular resistance in sodium pentobarbitone anesthetized rats was measured with a microsphere technique. When exposing the left scrotum to 33 and 37 degrees C for 30 min, no significant effects on blood flows were observed in comparison to those of the right side. Exposure to 41 degrees C caused a significant (p less than 0.05) decrease in vascular resistance of both testes and epididymides. The response was more pronounced at 43 degrees C. The Leydig cell function, as judged from the testosterone concentrations in plasma and testicular tissue after LH stimulation, was significantly (p less than 0.01) depressed at 41 and 43 degrees C. It was concluded that the impaired Leydig cell function was unrelated to testicular blood flow.