Final answer:
Testosterone is produced by Leydig cells, which are also known as interstitial cells in the testes. Leydig cells secrete testosterone, which is responsible for physical changes during puberty and spermatogenesis.
Step-by-step explanation:
Testosterone, an androgen, is a steroid hormone produced by Leydig cells (also known as interstitial cells) in the testes. These cells are located between the seminiferous tubules and are responsible for secreting testosterone.
During male embryonic development, Leydig cells start secreting testosterone by the seventh week, leading to the differentiation of male sexual organs. Testosterone levels increase during puberty and play a crucial role in physical changes and spermatogenesis (sperm production).
In addition to spermatogenesis, testosterone contributes to muscle development, bone growth, the development of secondary sex characteristics, and maintaining libido in both males and females.