Local effects of cortisol on testicular function in rats

Although there is an abundance of literature regarding the endocrine function of patients with glucocorticoid excess, there is little known about the effect on testicular function. Increases in impotency and decreased libido have been noted, but few of these studies examine spermatogenesis or testicular histology. It is hypothesized that elevated intratesticular cortisol levels might act at a local level to cause alterations in testicular function. This hypothesis was evaluated using intratesticular implants containing cortisol or placebo pellets in rats. Bilateral implants were placed in prepubertal animals to study testis growth and in adults to control for systemic versus local effects. As an additional control, unilateral pellets contained twice as much cortisol as those placed bilaterally, providing the same total dose. Plasma cortisol, FSH, LH and testosterone levels did not differ among the treatment groups. Quantitative morphometric analysis of seminiferous tubules showed a significant difference in the tubule diameter of the placebo treated and the cortisol treated animals in the adult. It would appear that a local intratesticular effect of cortisol may account, in part, for the alteration of testicular function.