While no single hormone directly increases testicle size in isolation, gonadotropins, specifically Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH), are the primary hormones that stimulate testicular growth and function, including increasing size.
Here's a more detailed explanation:
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Gonadotropins (FSH and LH): These hormones are released from the pituitary gland and travel to the testicles.
- LH (Luteinizing Hormone): LH stimulates Leydig cells within the testes to produce testosterone. While testosterone itself contributes to the overall development of male characteristics, including the testes, it is not the direct driver of initial testicular growth.
- FSH (Follicle-Stimulating Hormone): FSH acts on Sertoli cells within the seminiferous tubules. These tubules are critical for sperm production. FSH stimulates the growth and maturation of these tubules, contributing significantly to the overall increase in testicular size during puberty.
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Testosterone: This is the primary male sex hormone, and its production is stimulated by LH. Testosterone plays a crucial role in the development of secondary sexual characteristics, muscle mass, bone density, and overall male development. While it contributes to the functional maturity of the testes, the initial increase in testicular size is more directly related to the action of FSH on the seminiferous tubules.
In summary: Testicular growth is a complex process. While testosterone is vital for testicular function and male sexual development, the primary hormonal drivers of increased testicular size are the gonadotropins, FSH and LH. FSH stimulates the growth of the seminiferous tubules, which make up a significant portion of the testicular volume. LH stimulates testosterone production, which supports the overall development and function of the testes.
