Leydig cell impairment is generally associated with infertility, however, not all individuals suffering from decreased Leydig cell function will experience infertility or subfertility. Although Leydig cells are present in both male and female reproductive organs, dysfunction is most commonly seen in males.
Leydig Cells in Males
In males, Leydig cells are located next to the seminiferous tubules in the testes. These tubules contain the germ cells that eventually develop into the mature spermatozoa. Leydig cells respond to cyclical bursts of luteinizing hormone (LH), which is released from the pituitary gland. LH bonds to the Leydig cells, stimulating the cells into producing testosterone and other androgens (male hormones).
The testosterone-laden mixture, also known as interstitial cell stimulating hormone (ICSH), is converted into estrogen by the nearby granulosa cells. In addition, Leydig cells are also call interstitial cells because they support surrounding cell structures. Thus, Leydig cells and testosterone secretions directly affect and stimulate spermatogenesis (sperm cell development).Here are some conditions the affecting Leydig cells in males.
Leydig Cell Tumors
Leydig cell tumors are rare, comprising of only about 3 percent of all testicular tumors. The cause of Leydig cell tumors has not been proven, but there appears to be a connection between the overproduction of LH, which may increase the amount of testosterone that is converted into estrogen. Researchers theorize that Leydig cell tumors may be associated with a disorder involving the pituitary gland or hypothalamic system.
Approximately 20 percent of Leydig cell tumors are diagnosed in prepubescent boys, with the remainder occurring in males aged 20 to 60 years. In children, the tumors are always benign. In adult males, most tumors are also non-cancerous, however, about 10 percent of cases are malignant. Patients with Leydig cell tumors may experience swelling of the testes, decreased sex drive and infertility/subfertility.
Some scientists have made a correlation between age and a decline in Leydig cell function. Testosterone levels begin to peak at around age 30. Thereafter, there is a decline of approximately 1 percent per year. This does not indicate that all males will suffer from subfertility or infertility, as they grow older, however, in some individuals, the decline may be significant.
Hypogonadism can occur in all age groups, including the time of fetal development. It is characterized by the inability to produce testosterone. Hypogonadism can result from congenital defects, as well as injury to the testes, cancer and elevated levels of iron in the bloodstream. It may also be present with another condition. The result is the hypothalamic system is impaired.
Leydig Cell Hyperplasia
Leydig cell hyperplasia is characterized by multiple nodules occurring on the testes. The condition is usually benign, but may be present with other disorders or conditions. Leydig cell hyperplasia does not affect fertility in all males.
Other conditions that can affect Leydig cell function include cancer, cirrhosis of the liver, injury and exposure of the testes to prolonged heat.
Sertoli-Leydig Cell Tumor
In females, Leydig cells are located in the ovaries. Sertoli-Leydig tumors are malignant. Cancerous cells in the ovaries secrete androgens. This condition can cause deepening of the voice and excessive hair growth.
Leydig cell research is ongoing and the role of these cells in not yet fully understood. Nor is there agreement as to why Leydig cell dysfunction causes infertility.