Leydig cell
Overview
Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules
Seminiferous tubules
Seminiferous tubules are located in the testes, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa....

 in the testicle. They produce testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

 in the presence of luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...

 (LH). Leydig cells are polyhedral in shape, display a large prominent nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

, an eosinophilic
Eosinophilic
Eosinophilic refers to the staining of certain tissues, cells, or organelles after they have been washed with eosin, a dye.Eosin is an acidic dye; thus, the structure being stained is basic....

 cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 and numerous lipid-filled vesicles.
Leydig cells are named after the German anatomist Franz Leydig
Franz Leydig
Franz von Leydig , also Franz Leydig, was a German zoologist and comparative anatomist.- Life :Franz Leydig was born on May 21, 1821, in Rothenburg ob der Tauber . He was the only boy of three children born to Melchior Leydig, a Catholic and a minor public official, and Margareta, a Protestant...

, who discovered them in 1850.
Leydig cells release a class of hormones called androgens (19-carbon steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

s).
Encyclopedia
Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules
Seminiferous tubules
Seminiferous tubules are located in the testes, and are the specific location of meiosis, and the subsequent creation of gametes, namely spermatozoa....

 in the testicle. They produce testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

 in the presence of luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...

 (LH). Leydig cells are polyhedral in shape, display a large prominent nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

, an eosinophilic
Eosinophilic
Eosinophilic refers to the staining of certain tissues, cells, or organelles after they have been washed with eosin, a dye.Eosin is an acidic dye; thus, the structure being stained is basic....

 cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 and numerous lipid-filled vesicles.

Nomenclature

Leydig cells are named after the German anatomist Franz Leydig
Franz Leydig
Franz von Leydig , also Franz Leydig, was a German zoologist and comparative anatomist.- Life :Franz Leydig was born on May 21, 1821, in Rothenburg ob der Tauber . He was the only boy of three children born to Melchior Leydig, a Catholic and a minor public official, and Margareta, a Protestant...

, who discovered them in 1850.

Functions

Leydig cells release a class of hormones called androgens (19-carbon steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

s). They secrete testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

, androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...

 and dehydroepiandrosterone
Dehydroepiandrosterone
5-Dehydroepiandrosterone is a 19-carbon endogenous steroid hormone. It is the major secretory steroidal product of the adrenal glands and is also produced by the gonads and the brain. DHEA is the most abundant circulating steroid in humans....

 (DHEA), when stimulated by the pituitary
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...

 hormone luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...

 (LH). LH increases cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 desmolase
Cholesterol side-chain cleavage enzyme
Cytochrome P450, family 11, subfamily A, polypeptide 1 , often referred to as P450scc , is a mitochondrial enzyme associated with the conversion of cholesterol to pregnenolone. The gene name is CYP11A1...

 activity (an enzyme associated with the conversion of cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...

 to pregnenolone
Pregnenolone
Pregnenolone is a steroid hormone involved in the steroidogenesis of progesterone, mineralocorticoids, glucocorticoids, androgens, and estrogens. As such it is a prohormone. Pregnenolone sulfate is a GABAA antagonist and increases neurogenesis in the hippocampus.-Chemistry:Like other steroids,...

), leading to testosterone synthesis and secretion by Leydig cells.

Prolactin
Prolactin
Prolactin also known as luteotropic hormone is a protein that in humans is encoded by the PRL gene.Prolactin is a peptide hormone discovered by Henry Friesen...

 (PRL) increases the response of Leydig cells to LH by increasing the number of LH receptors expressed on Leydig cells.

The male Leydig cells in some species have also been shown to possess the biosynthetic machinery to manufacture testicular oxytocin
Oxytocin
Oxytocin is a mammalian hormone that acts primarily as a neuromodulator in the brain.Oxytocin is best known for its roles in sexual reproduction, in particular during and after childbirth...

 de novo
De novo
In general usage, de novo is a Latin expression meaning "from the beginning," "afresh," "anew," "beginning again." It is used in:* De novo transcriptome assembly, the method of creating a transcriptome without a reference genome...

, to be specific, in rats that can synthesize Vitamin C
Vitamin C
Vitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans and certain other animal species. In living organisms ascorbate acts as an antioxidant by protecting the body against oxidative stress...

 endogenously, and in guinea pigs that (like humans) require an exogenous source of Vitamin C (sodium ascorbate) in their diets.

Ultrastructure

The mammalian Leydig cell is a polyhedral epithelioid cell with a single eccentrically located ovoid nucleus. The nucleus contains one to three prominent nucleoli and large amounts of dark-staining peripheral heterochromatin. The acidophilic cytoplasm usually contains numerous membrane-bound lipid droplets and large amounts of smooth endoplasmic reticulum (SER). Besides the obvious abundance of SER with scattered patches of rough endoplasmic reticulum, several mitochondria are also prominent within the cytoplasm. Frequently, lipofuscin
Lipofuscin
Lipofuscin is the name given to finely granular yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. It is considered one of the aging or "wear-and-tear" pigments, found in the liver, kidney, heart muscle, adrenals, nerve cells, and ganglion cells...

 pigment and rod-shaped crystal-like structures 3 to 20 micrometres in diameter (Reinke's crystals) are found. These inclusions have no known function. No other interstitial cell within the testes has a nucleus or cytoplasm with these characteristics, making identification relatively easy.

Development

'Adult'-type Leydig cells differentiate in the post-natal testis and are quiescent until puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

. They are preceded in the testis by a population of 'fetal'-type Leydig cells from the 8th to the 20th week of gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....

, which produce enough testosterone for masculinisation of a male fetus.

Pathology

Leydig cells may grow uncontrollably and form a Leydig cell tumour
Leydig cell tumour
Leydig cell tumour, also Leydig cell tumor , interstitial cell tumour and interstitial cell tumor , is a member of the sex cord-stromal tumour group of ovarian and testicular cancers...

. These tumours are usually benign
Benign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

. They may be hormonally active, i.e. secrete testosterone.

Adrenomyeloneuropathy is another example of a disease affecting the Leydig cell: the patient's testosterone may fall despite higher-than-normal levels of LH and FSH.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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