[1][2] They are polyhedral in shape and have a large, prominent nucleus, an eosinophilic cytoplasm, and numerous lipid-filled vesicles.

[3] While Leydig cells are predominantly associated with testosterone production in the male testes, recent studies have revealed their presence and role in the ovaries of females.

These cells, located in the ovarian interstitial tissue, contribute to the production of androgens, including testosterone, which plays a significant role in the regulation of the menstrual cycle, ovulation, and overall reproductive health in women.

The activity of Leydig cells is particularly important in conditions such as polycystic ovary syndrome (PCOS), where excess androgen production can lead to symptoms such as hirsutism, acne, and infertility.

The acidophilic cytoplasm usually contains numerous membrane-bound lipid droplets and large amounts of smooth endoplasmic reticulum (SER).

[6] They are preceded in the testis by a population of fetal-type Leydig cells from the 8th to the 20th week of gestation, which produce enough testosterone for masculinisation of a male fetus.