Leydig Cells
லீடிக் செல்கள்
Do not confuse location with function. Leydig cells reside in the interstitial space, not the seminiferous tubules. If you misplace them, you fail the question.
The idea
Leydig cells, or interstitial cells, are situated in the interstitial spaces outside the seminiferous tubules. Their primary function is the synthesis and secretion of testicular hormones, specifically androgens like testosterone. These cells are regulated by the Luteinizing Hormone (LH) secreted by the anterior pituitary gland.
Why it matters
To provide the hormonal environment (testosterone) necessary for spermatogenesis and the development of secondary sexual characteristics.
NEET lens
NEET examiners frequently swap 'Leydig cells' with 'Sertoli cells' in matching questions. Remember: Leydig = Androgens; Sertoli = Nutrition. Focus on the regulatory axis: LH acts on Leydig cells, while FSH acts on Sertoli cells. This distinction has appeared in 7 papers since 2015.
Clinical significance
Failure of Leydig cells leads to hypogonadism, resulting in low testosterone levels. This manifests as delayed puberty, reduced muscle mass, and infertility. Without these cells, spermatogenesis remains incomplete.
Introduction
Leydig cells (interstitial cells of Leydig) are testosterone-producing cells located in the interstitial tissue between seminiferous tubules of the testis, stimulated by LH from the anterior pituitary.
Core concept
Location: interstitial (connective tissue) spaces between seminiferous tubules. Stimulation: LH (luteinizing hormone) from anterior pituitary → Leydig cell LH receptors → cAMP → StAR protein → cholesterol → testosterone synthesis. Testosterone functions: (1) Spermatogenesis (essential, high local concentration needed). (2) Development of male secondary sexual characters (puberty): voice deepening, facial/body hair, muscle growth, bone density. (3) Anabolic effects: protein synthesis → muscle mass. (4) Sex drive (libido). (5) Fetal development: AMH + testosterone → male genitalia development. Regulation: testosterone → negative feedback on hypothalamus (↓GnRH) + pituitary (↓LH) → reduces its own production.
Go deeper
Androgen-binding protein (ABP): Sertoli cells secrete ABP in response to FSH → ABP binds testosterone → maintains high local testosterone concentration in seminiferous tubule lumen (needed for spermatogenesis). Circulating testosterone is mostly bound to SHBG (sex hormone-binding globulin); only free (unbound) testosterone is biologically active.
From Class 10
The testes produce both sperm and the male hormone testosterone. While seminiferous tubules produce sperm, a different set of cells — the Leydig cells — produce testosterone.