Testicular Steroidogenesis: Production and Regulation of Testosterone and Dihydrotestosterone

The document from 2017 explores the production and regulation of testosterone (T) and dihydrotestosterone (DHT) in the testes, particularly in Leydig cells, and the impact of genetic disorders on these processes. It describes the classic pathway of T synthesis from cholesterol and an alternative "backdoor" pathway for DHT synthesis that bypasses T. The paper notes that genetic defects in steroidogenesis can lead to congenital adrenal hyperplasia (CAH) and disorders of sexual development. It also discusses the differences in steroidogenesis between humans and rodents, the limited conversion of pregnenolone to androstenedione in humans, and the predominance of the delta 4 pathway in rodent testosterone production. The document emphasizes the need for further research to fully understand androgen regulation and action, particularly in aging and various physiological conditions, and the development of synthetic androgens or selective androgen receptor modulators (SARMs) to reduce side effects. It also highlights the importance of androgens throughout male life and their role in sexual differentiation, function, and reproduction, while acknowledging the potential of androgens as anti-aging agents despite their side effects.