Endocrine control of spermatogenesis: Role of FSH and LH/ testosterone

Area of Science:

• Reproductive Toxicology
• Endocrinology

Background:

• Testicular function, including sperm and androgen production, is crucial for preclinical safety evaluation.
• Testicular toxicity is more prevalent than ovarian toxicity.
• Understanding the roles of gonadotropins and androgens is key to assessing reproductive health.

Approach:

• This chapter examines the histological effects of disrupted reproductive endocrinology in rats, dogs, and nonhuman primates.
• It reviews the current knowledge on the functions of gonadotropins and androgens in testicular health.

Key Points:

• Species-specific responses to endocrine disturbances were observed, with rodents showing different initial effects and less pronounced end-stage spermatogenic involution compared to dogs and primates.
• Luteinizing hormone (LH)/testosterone and follicle-stimulating hormone (FSH) are critical for testicular function.
• The relative importance of LH and FSH varies between rodents and primates.

Conclusions:

• Both LH/testosterone and FSH are generally required for normal spermatogenesis in non-seasonal species.
• Differential responses highlight the importance of species selection in toxicological studies.
• Further research into the specific mechanisms of gonadotropin and androgen action is warranted.