Testosterone in the testes is under the pulsatile control of the pituitary luteinizing hormone. Leydig cells secrete this hormone. The cyclic nucleotide phosphodiesterase (PDE) is modulated by the response to LH. The presence of PDEs in Leydig cells is not fully defined. In Leydig cells, PDE8A is expressed and is a crucial regulator of LH signalling and steroidogenesis. In a Leydig cell isolated from PDE8A knockout mice, a four-fold increase in the sensitivity of LH for Testosterone production was detected. These cells are named after the great German anatomist Franz Leydig, who discovered them between 1850 and 1851.
During the 1930s, the male hormone was shown to be androgen or testosterone, its endocrine actions were studied extensively, and the role of the pituitary gland in regulating testicular function was demonstrated. From the 1931s through the 1951s, Leydig cells came back into favour as endocrine cells, although some uncertainty persisted, and there was still no direct evidence that Leydig cells produced androgen. The direct evidence came from histochemistry in 1957 and biochemistry in 1964.
Leydig Cells Histology
Franz Leydig first described the testicular cells in 1851 that now bears his name. Their evidence seemed compelling at the time but was necessarily circumstantial because there was no direct proof that Leydig cells produced a male androgenic hormone. Over the following decades, workers found additional evidence that these cells had an endocrine function, but other findings cast doubt on the hypothesis, and increasing skepticism developed about the earlier evidence. Many influential reproductive biologists suspected that the seminiferous tubules were the actual source of male hormones.
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The interstitial cell of Leydig is stimulated by LH when it enters the testes to make and release testosterone into the testes and the blood. It appears in men during adolescence and stimulates spermatogenesis. Many external characteristics that grow in an individual due to the production of this hormone are deepening of the voice, facial hair growth, axillary and pubic hair growth.
To inhibit the release of GnRH, FSH, and LH, a negative feedback system occurs in males with levels of testosterone rising. It affects the hypothalamus and anterior pituitary for those releases. When the sperm count is too high, inhibit hormone is produced by sterling cells in the blood. To slow down spermatogenesis, GnRH and FSH are released. The release of sterling decreases if the sperm count becomes 23million/ml. This was how the interstitial cells of Leydig were responsible for the production and secretion of testosterone.
Difference Between Sertoli cells and Leydig cells
The table below precisely describes the difference between Sertoli cells and Leydig cells.
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Sertoli Cells |
Leydig Cells |
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These cells are Nutritive cells that are found inside the seminiferous tubules. |
Cells That are present outside the seminiferous tubules in the interstitial species. |
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Nourishment to the male germ cell is provided by them. |
These cells secrete androgen. |
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FSH stimulates sterling cells. |
LH stimulates Leydig cells. |
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The functional receptor for FSH is expressed by a Sertoli cell. |
LH keeps a track of the male reproductive tract and spermatogenesis. |
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Peptide hormone inhibin B is secreted. |
Leydig cells secrete testosterone which is the male sex hormone. |
Leydig Cells Function
Leydig cells function was made easy to understand by the introduction of important methodology approaches of Larry Ewing. It first started in 1850 when rabbits’ testicles were experimented on, and it led to the production of testosterone. Adult Leydig cells produce progesterone more than testosterone. They respond differently to gonadotropin treatments. Leydig cells respond very slowly to these gonadotropins and produce 20 to 30 times fewer steroids than adrenal cells. Leydig cell’s function is well observed in uncompromising three-dimensional testis architecture. From 1850, it took over a century to discover the proper functions of Leydig cells.
The primary source of androgen and testosterone in males is Leydig cells. These cells are associated with decreased ratios of testicular hormones to gonadotropins and are more frequent in biopsies with impaired spermatogenesis. Thus micronodules are a marker of testicular failure in men and also in Leydig cells histology.