Leydig cells

(noun)

Also known as interstitial cells of Leydig, these are found adjacent to the seminiferous tubules in the testicle and produce testosterone in the presence of luteinizing hormone.

Related Terms

  • sertoli cells
  • follicle-stimulating hormone
  • Luteinizing hormone
  • testes
  • testicle

Examples of Leydig cells in the following topics:

  • Hormonal Regulation of the Male Reproductive System

    • However, it is known that initiation of spermatogenesis occurs at puberty due to the interaction of the hypothalamus, pituitary gland, and Leydig cells.
    • The Leydig cells are also capable of producing estradiol in addition to their main product, testosterone.
    • In the testes, LH binds to receptors on Leydig cells, which stimulates the synthesis and secretion of testosterone.
    • Testosterone is made in the interstitial cells of the testes.
    • Inhibin is secreted by the Sertoli cells and acts to decrease the levels of FSH.
  • Testicular Cancer

    • Although testicular cancer can be derived from any cell type found in the testicles, more than 95% of testicular cancers are germ cell tumors .
    • Most of the remaining 5% are sex cord-gonadal stromal tumors derived from Leydig cells or Sertoli cells.
    • Most testicular germ cell tumors have too many chromosomes, and most often they are triploid to tetraploid.
    • About half of germ cell tumors of the testis are seminomas.
  • Testes

    • These are lined with a layer of germ cells that develop into sperm cells (also known as spermatozoa or male gametes) from puberty into old age.
    • The developing sperm travels through the seminiferous tubules to the rete testis located in the mediastinum testis, to the efferent ducts, and then to the epididymis where newly-created sperm cells mature.
    • Leydig cells located between seminiferous tubules produce and secrete testosterone and other androgens important for sexual development and puberty, including secondary sexual characteristics such as facial hair and sexual behavior.
    • The sertoli cells are the testes’ somatic cells, necessary for testis development and spermatogenesis.
  • Male and Female Gonads

    • Progesterone and estrogen are secreted by granulosal cells, whereas testosterone is produced by thecal cells.
    • Prior to ovulation, follicle-stimulating hormone is secreted by the granulosal cells that convert testosterone into estradiol.
    • Testosterone is secreted by Leydig cells, which are located between the seminiferous tubules.
  • Aging and the Endocrine System

    • This decrease in responsiveness can be attributed to a decrease in IGF-I signaling pathways with advanced cell age.
    • Testosterone is a steroid hormone secreted by the Leydig cells.
    • Estradiol is the female equivalent of testosterone and is secreted from granulosa cells.
    • In vitro, cells treated with testosterone demonstrated a decrease in Ab release.
    • Estrogen acts on the nucleus of the cell by binding with the nuclear endoplasmic reticulum (ER).
  • Puberty

    • LH stimulates the Leydig cells of the testes to make testosterone and blood levels begin to rise.
    • For females, as the amplitude of LH pulses increases, the theca cells of the ovaries begin to produce testosterone and smaller amounts of progesterone.
    • Much of the testosterone moves into nearby cells called granulosa cells.
    • Smaller increases of FSH induce an increase in the aromatase activity of these granulosa cells, which converts most of the testosterone to estradiol for secretion into the circulation.
  • Specific T-Cell Roles

    • T helper cells assist the maturation of B cells and memory B cells while activating cytotoxic T cells and macrophages.
    • Differentiation into helper T cell subtypes occurs during clonal selection following T cell activation of naive T cells.
    • Cytotoxic T cells (TC cells, or CTLs) destroy virus-infected cells and tumor cells, and cause much of the damage in in transplant rejection and autoimmune diseases.
    • Memory T cells comprise two subtypes: central memory T cells (TCM cells) and effector memory T cells (TEM cells), which have different properties and release different cytokines.
    • Regulatory T cells (Treg cells), also known as suppressor T cells, are crucial for the maintenance of immunological tolerance.
  • Natural Killer Cells

    • The role of NK cells is similar to that of cytotoxic T cells in the adaptive immune response.
    • NK cells provide rapid responses to virus-infected cells and respond to tumor formation by destroying abnormal and infected cells.
    • NK cells use wo cytolytic granule-mediated apoptosis to destroy abnormal and infected cells.
    • Virus-infected cells destroyed by cell lysis release their replicated virus particles into the body, which infects other cells.
    • Cells that are osponized with antibodies are easier for NK cells to detect and destroy.
  • Lymphoid Cells

    • The three major types of lymphocyte are T cells, B cells, and natural killer cells.
    • If cancer cells evade NK cell detection for long enough, however, they can grow into tumors that are more resistant to NK cell activity.
    • T cells are involved in cell-mediated immunity whereas B cells are primarily responsible for humoral immunity.
    • There are two types of T cells involved in adaptive, cell-mediated immunity.
    • Following activation, B cells and T cells leave a lasting legacy of the antigens they have encountered in the form of memory cells.
  • Maturation of T Cells

    • T cells belong to a group of white blood cells known as lymphocytes and play a central role in the cell-mediated branch of the adaptive immune system.
    • They are distinguished from other lymphocytes, such as B cells and natural killer cells (NK cells), by the presence of a T cell receptor (TCR) on the cell surface.
    • T cells can be either helper T cells or cytoxic T cells based on whether they express CD4 (helper) or CD8 (cytotoxic) glycoprotein.
    • A T cell is then signaled by the thymus to become a CD4+ cell by reducing expression of its CD8 cell surface receptors.
    • The remaining cells exit the thymus as mature naive T cells.
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