Veterinary Andrology and Reproductive Techniques

TESTOSTERONE

• Testosterone is a steroid hormone soluble in oil and alcohol but not in water.
• Acetate is converted to cholesterol which in turn is converted to progesterone – androstenedione – testosterone (16 times more active than androstenedione in bulls).

Functions of Testosterone

• Sexual differentiation of external male genetalia and descent of the testes into scrotum in fetuses or neonates.
• Keratinization of the preputial epithelium, separation of glans penis from prepuce, growth of the penis and prepuce at puberty.
• Growth and maintenance of accessory sex glands.
• Sexual desire or libido, ability for normal erection and ejaculation.
• Secondary sexual characteristics like hair or horn growth, male attitudes, voice, increased bone thickness, increased muscle tissue with different distribution of fat from female.
• Maintenance of secretory and absorptive activities and structure of efferent ducts, epididymis and ductus deferens including ampulla.
• Spermiogenesis – development and maturation of spermatids and spermatozoa.

In stallion the androstenedione is the major androgen.