Are adrenal and testicular androgen levels correlated?

To investigate the reported correlation between adrenal and testicular serum androgen levels, testosterone, DHEAS and androstenedione were measured in the serum of 92 healthy young males. Testosterone and androstenedione were found to have a weak but statistically significant correlation, while no correlation existed between testosterone and DHEAS, or DHEAS and androstenedione. These results indicate that although common steroidogenic pathways lead to androgen synthesis in both adrenals and testes, the regulation of steroid production in these glands is influenced by different factors. The correlation of testosterone with androstenedione can be attributed to their peripheral interconversion as well as to the fact that half of androstenedione is of testicular origin. Various other aspects of the androgen regulation mechanism such as ACTH stimulation and the role of aging, are presented and discussed.