Thermoregulation of the scrotum and testis: studies in animals and significance for man.

This article reviews the extensive information available from experiments on animals concerning the thermal monitoring provided by the scrotum. Cutaneous temperature receptors initiate responses which follow unique pathways and undergo "switching" processing within the central nervous system. These pathways evoke reflex responses which are subject to control from receptors in other regions of the body, including the skin and temperature sensitive neurones in the brain and spinal cord. The local thermoregulatory responses of the scrotum, e.g., sweating and vasomotor changes, clearly have a role to play in the protection of the testis against temperature elevation in both man and animals. It is as yet more difficult to propose how general reflex responses may be of benefit in the protection of spermatogenesis against heat damage. This meeting should provide the stimulus for further work. The need is urgent since it may also provide a means to apply this knowledge to a better understanding of male infertility and possibly to speed the development of male methods of fertility regulation.