Table of Contents
Definition
Leydig cells are named after the name of the German scientist Franz Leydig, who discovered them in 1850.
Leydig cells, often referred to as interstitial cells of Leydig and interstitial cells of the testes, are located next to the seminiferous tubules in the testicle and create testosterone when luteinizing hormone (LH) is present. They feature a polyhedral structure, an eosinophilic cytoplasm, a large, apparent nucleus, and plenty of vesicles packed with lipids.
Sperm are produced in coiled seminiferous tubules found in each testicular lobule. Sertoli cells and male germ cells (spermatogonia) are the two types of cells that line the interior of each seminiferous tubule. Sertoli cells nourish the male germ cells while they go through meiotic divisions that ultimately result in the formation of sperm. Leydig cells or interstitial cells are found in the areas outside the seminiferous tubules known as interstitial spaces.
Androgens are produced and secreted by Leydig cells and are testicular hormones. There are also other immunologically capable cells present.
Structure
Leydig cells are located around the seminiferous tubules constituting groups of one to ten cells. These cells are typically polygonal, having an eosinophilic cytoplasm, a sizable, round nucleus, and a prominent nucleolus. The amount of lipids is high.
These cells produce testosterone; therefore, they have characteristics of steroid-secreting cells, such as a significant number of mitochondria with tubulovesicular cristae, a large and well-developed smooth endoplasmic reticulum, and numerous vast and enormous lipid droplets.
Lipofuscin, which appears as numerous rounded irregular entities and is another frequent observation in Leydig cells, is a lipid droplet accumulation found in lysosomes.
Leydig cells are known to contain Reinke’s crystalloids, which are pale-coloured cytoplasmic inclusions. These crystals often have a linear arrangement and a rod-like or cylindrical shape.
Functions
The primary source of androgen or testosterone in males is the Leydig cell. This physiology enables them to significantly influence various critical physiological functions in males, including spermatogenesis, the regulation of sexual development, and the maintenance of secondary sexual traits and behaviours.
These vital processes begin with androgen production within Leydig cells, which is regulated and controlled by various factors, primarily luteinizing hormone (LH). Leydig cells produce steroid (androgen) more effectively due to their high lipid content and well-developed smooth endoplasmic reticulum.
Leydig cells release androgens as male embryos develop, which triggers the formation of the Wolffian duct and other male urogenital structures. The formation of female genitalia is inhibited by the anti-Mullerian hormone produced by Sertoli cells. Adult Leydig cells replace the infantile ones in adults, which helps to maintain androgen levels throughout life.
Clinical Importance
Young males sometimes develop testicular cancers, a rare subtype called Leydig cell tumour. There are no distinguishing ultrasound features to differentiate this tumour, despite imaging procedures like CT and ultrasound being crucial for assessment.
Histology allows the proper diagnosis of Leydig cell tumours and their characteristics, such as Reinke’s crystals. Radical orchiectomy is the standard treatment.
Klinefelter syndrome is the most common sex chromosome disease in males. It occurs from having an additional X chromosome (47, XXY). Leydig cell hyperplasia commonly occurs if Klinefelter syndrome is present.
Histological analysis can distinguish between Leydig cell hyperplasia and Leydig cell tumours. Granulomatous disease and lymphoma should also be considered, depending on the age and medical history of the patient.
Another condition that affects the Leydig cell is adrenomyeloneuropathy. In this condition, testosterone levels may drop despite higher-than-average amounts of luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
Related Links:
- Human Reproductive System
- Sexual Reproduction – Male and Female Reproductive System
- Important Notes For NEET Biology – Human Reproduction
Main Page:BYJU’S NEET
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