Difference Between Seminiferous Tubules and Leydig Cells

The key difference between seminiferous tubules and Leydig cells is that seminiferous tubules are the sites of sperm synthesis, maturation and transportation in the male reproductive system while Leydig cells are the cells present in interstitial spaces that produce and secrete the male sex hormone testosterone.

The male reproductive system consists of different parts. Testis or testicle is one of the main structures of it. It produces male gametes or sperms and secretes sex hormone. Testis comprises of highly coiled tubes called seminiferous tubules. Seminiferous tubules contain up to 90% of the testis. These tubules are the site of sperm production, maturation and transportation. Leydig cells are the endocrine components of the testis that secrete testosterone, which is the male sexual hormone. Leydig cells are found in the interstitial tissue of testis.

CONTENTS

1. Overview and Key Difference
2. What are Seminiferous Tubules 
3. What are Leydig Cells
4. Similarities Between Seminiferous Tubules and Leydig Cells
5. Side by Side Comparison – Seminiferous Tubules vs Leydig Cells in Tabular Form
6. Summary

What are Seminiferous Tubules?

Seminiferous tubules are highly coiled structures located in the male reproductive system. These tubules are the site of sperm production, maturation and transportation within the testis. Structurally, seminiferous tubules are about 150-300 µm in diameter and 30-80 cm long. They are also surrounded by a basal lamina. Therefore, the basal lamina works as a barrier between seminiferous tubules and interstitial space. Seminiferous tubules are lined with cells called Sertoli cells. Sertoli cells are long columnar cells extending from the basal lamina to the tubule lumen. They are present in the tubule walls. Moreover, seminiferous tubules have male germ cells.

Seminiferous tubules produce sperm cells via meiosis. This process is called spermatogenesis, and in this process, immature male germ cells transform into mature sperms. Sertoli cells provide mechanical and nutritive support for spermatogenic cells.

What are Leydig Cells?

Leydig cells or interstitial cells are the cells present in the interstitial space of the testis. In fact, they are located in the connective tissue that surrounds the seminiferous tubules. The main function of Leydig cells is the synthesis and secretion of the male sex hormone: testosterone. Therefore, Leydig cells are the endocrine component of the testis. Testosterone hormone is responsible for the regulation of secondary sex characteristics. Moreover, it is responsible for the growth and maintenance of the cells of the germinal epithelium. Other than testosterone, Leydig cells also release androstenedione and dehydroepiandrosterone (DHEA), which are androgens.

Leydig cells are polyhedral epithelial cells which are variable in size. They are supplied by capillaries. Moreover, they have a distinct nucleus.

What are the Similarities Between Seminiferous Tubules and Leydig Cells?

• Seminiferous tubules and Leydig cells are two components of testis of the male reproductive system.
• Leydig cells are found adjacent to the seminiferous tubules.
• Both are important for spermatogenesis.
• Basal lamina separates Leydig cells from seminiferous tubules.

What is the Difference Between Seminiferous Tubules and Leydig Cells?

Seminiferous tubules are a network of tubes that work as the sites for sperm production, maturation and transportation in the male reproductive system. Leydig cells or interstitial cells are the cells that synthesize and secrete testosterone. So, this is the key difference between seminiferous tubules and Leydig cells. Moreover, seminiferous tubules are located inside the testis, and they account for 90% of the testis. But, in contrast, Leydig cells are found in the interstitial space of the testis. Besides, structurally, seminiferous tubules are a network of tubes, while Leydig cells are polyhedral shaped cells.

The below infographic of the difference between seminiferous tubules and Leydig cells shows a side by side comparison of seminiferous tubules and Leydig cells.

Summary – Seminiferous Tubules vs Leydig Cells

Seminiferous tubules and Leydig cells are found in the testis of the male reproductive system. Seminiferous tubules are responsible for the production, maturation and transportation of sperms while Leydig cells are responsible for the production and secretion of the male sex hormone testosterone. Thus, this is the key difference between seminiferous tubules and Leydig cells.

Reference:

1. “Animal Reproductive System – Male Systems”. Encyclopedia Britannica, 2020, Available here.
2. “Leydig Cell”. En.Wikipedia.Org, 2020, Available here.

Image Courtesy:

1. “Anatomy and physiology of animals The testis & a magnified seminferous tubule” – The original uploader was Sunshineconnelly at English Wikibooks. – Transferred from en.wikibooks to Commons by Adrignola using CommonsHelper (CC BY 3.0) via Commons Wikimedia

2. “Leydig cells – very high mag” By Nephron – Own work (CC BY-SA 3.0) via Commons Wikimedia