Plasma testosterone levels and delta 5-3 beta-hydroxysteroid dehydrogenase activity in the testis of the rat following prolonged exposure to stress.

Exposure of male CSF rats to a signalled, unpredictable 60-day stress regimen induced a significant elevation in circulating testosterone levels at Days 1 and 60 which was abolished by castration. Small morphological changes were seen in the Leydig cells in the early days of stressing. A significant increase in 3 beta-HSD activity was seen by 5 days of stress, indicating increased steroidogenic activity.