Which hormone is predominantly produced in the testes?

Testosterone is predominantly produced in the testes and is the primary male sex hormone responsible for the development of male reproductive tissues, such as the testes and prostate, as well as the promotion of secondary sexual characteristics, including increased muscle and bone mass and the growth of body hair.

The Leydig cells in the testes produce testosterone in response to luteinizing hormone (LH) released from the anterior pituitary gland. This hormone plays a crucial role in male sexual development and function, from fetal development through adulthood.

In contrast, estrogen and progesterone are primarily associated with female reproductive health and are produced mainly in the ovaries, while cortisol is a steroid hormone produced by the adrenal glands and is involved in various functions related to stress response and metabolism. Each of these hormones has distinct roles and production sites within the endocrine system, making testosterone the clear answer in this context.