Summary. A single dose of EDS was given to mature male rats and interstitial fluid (IF) was collected to determine the potency of mitogenic and steroidogenic activities therein. The potency of the factor stimulating testosterone secretion in vitro by Percoll-purified Leydig cells was significantly elevated 2 weeks after EDS, whilst the potency of mitogenic activities (stimulation of DNA synthesis by BALB/c 3T3 cells) was not elevated until 4 weeks after EDS treatment.
This study suggests that two separate factors, one with mitogenic and the other steroidogenic activity, may be involved in the response of Leydig cells after EDS administration. The mitogenic factor may play a role in Leydig cell regeneration whereas the testosterone-stimulating factor may be involved in testicular testosterone homeostasis.