Luteinizing hormone
Encyclopedia
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 (ICSH), it stimulates Leydig cell
production of testosterone
. It acts synergistically with FSH
.
ic glycoprotein
. Each monomer
ic unit is a glycoprotein
molecule; one alpha and one beta subunit make the full, functional protein.
Its structure is similar to that of the other glycoprotein hormones, follicle-stimulating hormone
(FSH), thyroid-stimulating hormone
(TSH), and human chorionic gonadotropin
(hCG). The protein dimer contains 2 glycopeptidic subunits, labeled alpha and beta subunits, that are non-covalently associated (i.e., without any disulfide bridge linking them):
The 92-amino acid long LH alpha subunit in humans has the following sequence:
NH2 – Ala – Pro – Asp – Val – Gln – Asp – Cys – Pro – Glu – Cys – Thr – Leu – Gln – Glu – Asn – Pro – Phe – Phe – Ser – Gln – Pro – Gly – Ala – Pro – Ile – Leu – Gln – Cys – Met – Gly – Cys – Cys – Phe – Ser – Arg – Ala – Tyr – Pro – Thr – Pro – Leu – Arg – Ser – Lys – Lys – Thr – Met – Leu – Val – Gln – Lys – Asn – Val – Thr – Ser – Glu – Ser – Thr – Cys – Cys – Val – Ala – Lys – Ser – Tyr – Asn – Arg – Val – Thr – Val – Met – Gly – Gly – Phe – Lys – Val – Glu – Asn – His – Thr – Ala – Cys – His – Cys – Ser – Thr – Cys – Tyr – Tyr – His – Lys – Ser – OH
NH2 – Ser – Arg – Glu – Pro – Leu – Arg – Pro – Trp – Cys – His – Pro – Ile – Asn – Ala – Ile – Leu – Ala – Val – Glu – Lys – Glu – Gly – Cys – Pro – Val – Cys – Ile – Thr – Val – AsnThr – Thr – Ile – Cys – Ala – Gly – Tyr – Cys – Pro – Thr – Met – Met – Arg – Val – Leu – Gln – Ala – Val – Leu – Pro – Pro – Leu – Pro – Gln – Val – Val – Cys – Thr – Tyr – Arg – Asp – Val – Arg – Phe – Glu – Ser – Ile – Arg – Leu – Pro – Gly – Cys – Pro – Arg – Gly – Val – Asp – Pro – Val – Val – Ser – Phe – Pro – Val – Ala – Leu – Ser – Cys – Arg – Cys – Gly – Pro – Cys – Arg – Arg – Ser – Thr – Ser – Asp – Cys – Gly – Gly – Pro – Lys – Asp – His – Pro – Leu – Thr – Cys – Asp – His – Pro – Gln – Leu – Ser – Gly – Leu – Leu – Phe – Leu – OH
The different composition of these oligosaccharide
s affects bioactivity and speed of degradation. The biologic half-life
of LH is 20 minutes, shorter than that of FSH (3–4 hours) and hCG (24 hours).
for the alpha subunit is located on chromosome 6q12.21.
The luteinizing hormone beta subunit gene is localized in the LHB/CGB gene cluster on chromosome 19q13.32. In contrast to the alpha gene activity, beta LH subunit gene activity is restricted to the pituitary gonadotropic cells. It is regulated by the gonadotropin-releasing hormone
from the hypothalamus
. Inhibin, activin, and sex hormones do not affect genetic activity for the beta subunit production of LH.
The release of LH at the pituitary gland is controlled by pulses of gonadotropin-releasing hormone
(GnRH) from the hypothalamus
. Those pulses, in turn, are subject to the estrogen feedback from the gonads.
and, in women, high after menopause
. As LH is secreted as pulses, it is necessary to follow its concentration over a sufficient period of time to get a proper information about its blood level.
During the reproductive years, typical levels are between 1-20 IU/L. Physiologic high LH levels are seen during the LH surge (v.s.); typically they last 48 hours.
. LH can be detected by urinary ovulation predictor kits (OPK, also LH-kit) that are performed, typically daily, around the time ovulation may be expected. The conversion from a negative to a positive reading would suggest that ovulation is about to occur within 24–48 hours, giving women two days to engage in sexual intercourse
or artificial insemination
with the intentions of conceiving.
Tests may be read manually using a colour-change paper strip, or digitally with the assistance of reading electronics.
Tests for Luteinising hormone may be combined with testing for estradiol
in tests such as the Clearblue fertility monitor
.
The sensitivity of LH tests are measured in milli international unit, with tests commonly available in the range 10-40 m.i.u.
As sperm can stay viable in the woman for several days, LH tests are not recommended for contraceptive practices, as the LH surge typically occurs after the beginning of the fertile window.
[note: photo shows "negative" results in the top strip, i.e., no LH surge, and "positive" results in the bottom strip. *This information needs editing. An LH surge will cause the test line (on the left) to be darker in colour than the strip on the right (depending on the brand you buy; follow package insert instructions for interpreting results). Women with PCOS may have LH in their urine throughout their cycle, causing their tests to appear coloured throughout the cycle as displayed in the bottom strip. ]
of pituitary or central origin, LH and FSH levels may be in the reproductive range instead of the low levels typical for their age.
During the reproductive years, relatively elevated LH is frequently seen in patients with the polycystic ovary syndrome
; however, it would be unusual for them to have LH levels outside of the normal reproductive range.
Conditions with very low LH secretions are:
Often, hCG medication is used as an LH substitute because it activates the same receptor. Medically used hCG is derived from urine of pregnant women, is less costly, and has a longer half-life than LH.
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation
Ovulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
and development of the corpus luteum
Corpus luteum
The corpus luteum is a temporary endocrine structure in mammals, involved in production of relatively high levels of progesterone and moderate levels of estradiol and inhibin A...
. In males, where LH had also been called interstitial cell-stimulating hormone (ICSH), it stimulates Leydig cell
Leydig cell
Leydig cells, also known as interstitial cells of Leydig, are found adjacent to the seminiferous tubules in the testicle. They produce testosterone in the presence of luteinizing hormone...
production of 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...
. It acts synergistically with FSH
Follicle-stimulating hormone
Follicle-stimulating hormone is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone act...
.
Structure
LH is a heterodimerProtein dimer
In biochemistry, a dimer is a macromolecular complex formed by two, usually non-covalently bound, macromolecules like proteins or nucleic acids...
ic glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
. Each monomer
Monomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
ic unit is a glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
molecule; one alpha and one beta subunit make the full, functional protein.
Its structure is similar to that of the other glycoprotein hormones, follicle-stimulating hormone
Follicle-stimulating hormone
Follicle-stimulating hormone is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone act...
(FSH), thyroid-stimulating hormone
Thyroid-stimulating hormone
Thyrotrophin-stimulating hormone is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid gland.- Physiology :...
(TSH), and human chorionic gonadotropin
Human chorionic gonadotropin
Human chorionic gonadotropin or human chorionic gonadotrophin is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast .. Some tumors make this hormone; measured elevated levels when the patient is not...
(hCG). The protein dimer contains 2 glycopeptidic subunits, labeled alpha and beta subunits, that are non-covalently associated (i.e., without any disulfide bridge linking them):
- The alpha subunits of LH, FSH, TSH, and hCG are identical, and contain 92 amino acids in human but 96 amino acids in almost all other vertebrate species (glycoprotein hormones do not exist in invertebrates).
The 92-amino acid long LH alpha subunit in humans has the following sequence:
NH2 – Ala – Pro – Asp – Val – Gln – Asp – Cys – Pro – Glu – Cys – Thr – Leu – Gln – Glu – Asn – Pro – Phe – Phe – Ser – Gln – Pro – Gly – Ala – Pro – Ile – Leu – Gln – Cys – Met – Gly – Cys – Cys – Phe – Ser – Arg – Ala – Tyr – Pro – Thr – Pro – Leu – Arg – Ser – Lys – Lys – Thr – Met – Leu – Val – Gln – Lys – Asn – Val – Thr – Ser – Glu – Ser – Thr – Cys – Cys – Val – Ala – Lys – Ser – Tyr – Asn – Arg – Val – Thr – Val – Met – Gly – Gly – Phe – Lys – Val – Glu – Asn – His – Thr – Ala – Cys – His – Cys – Ser – Thr – Cys – Tyr – Tyr – His – Lys – Ser – OH
- Note: The carbohydrate moiety is linked to the asparagine at positions 52 and 78.
- The beta subunits vary. LH has a beta subunit of 120 amino acids (LHB) that confers its specific biologic action and is responsible for the specificity of the interaction with the LH receptor. This beta subunit contains an amino acid sequence that exhibits large homologies with that of the beta subunit of hCGHuman chorionic gonadotropinHuman chorionic gonadotropin or human chorionic gonadotrophin is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast .. Some tumors make this hormone; measured elevated levels when the patient is not...
and both stimulate the same receptor. However, the hCG beta subunit contains an additional 24 amino acids, and the two hormones differ in the composition of their sugar moieties.
NH2 – Ser – Arg – Glu – Pro – Leu – Arg – Pro – Trp – Cys – His – Pro – Ile – Asn – Ala – Ile – Leu – Ala – Val – Glu – Lys – Glu – Gly – Cys – Pro – Val – Cys – Ile – Thr – Val – AsnThr – Thr – Ile – Cys – Ala – Gly – Tyr – Cys – Pro – Thr – Met – Met – Arg – Val – Leu – Gln – Ala – Val – Leu – Pro – Pro – Leu – Pro – Gln – Val – Val – Cys – Thr – Tyr – Arg – Asp – Val – Arg – Phe – Glu – Ser – Ile – Arg – Leu – Pro – Gly – Cys – Pro – Arg – Gly – Val – Asp – Pro – Val – Val – Ser – Phe – Pro – Val – Ala – Leu – Ser – Cys – Arg – Cys – Gly – Pro – Cys – Arg – Arg – Ser – Thr – Ser – Asp – Cys – Gly – Gly – Pro – Lys – Asp – His – Pro – Leu – Thr – Cys – Asp – His – Pro – Gln – Leu – Ser – Gly – Leu – Leu – Phe – Leu – OH
The different composition of these oligosaccharide
Oligosaccharide
An oligosaccharide is a saccharide polymer containing a small number of component sugars, also known as simple sugars...
s affects bioactivity and speed of degradation. The biologic half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of LH is 20 minutes, shorter than that of FSH (3–4 hours) and hCG (24 hours).
Genes
The geneGene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
for the alpha subunit is located on chromosome 6q12.21.
The luteinizing hormone beta subunit gene is localized in the LHB/CGB gene cluster on chromosome 19q13.32. In contrast to the alpha gene activity, beta LH subunit gene activity is restricted to the pituitary gonadotropic cells. It is regulated by the gonadotropin-releasing hormone
Gonadotropin-releasing hormone
Gonadotropin-releasing hormone , also known as Luteinizing-hormone-releasing hormone and luliberin, is a tropic peptide hormone responsible for the release of follicle-stimulating hormone and luteinizing hormone from the anterior pituitary. GnRH is synthesized and released from neurons within...
from the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
. Inhibin, activin, and sex hormones do not affect genetic activity for the beta subunit production of LH.
Activity
In both males and females, LH is essential for reproduction.- In females, at the time of menstruation, FSH initiates follicular growth, specifically affecting granulosa cellGranulosa cellA granulosa cell or follicular cell is a somatic cell of the sex cord that is closely associated with the developing female gamete in the ovary of mammals.-Anatomy and function:...
s. With the rise in oestrogens, LH receptors are also expressed on the maturing follicle that produces an increasing amount of estradiolEstradiolEstradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
. Eventually at the time of the maturation of the follicle, the oestrogen rise leads via the hypothalamic interface to the “positive feed-back” effect, a release of LH over a 24- to 48-hour period. This 'LH surge' triggers ovulationOvulationOvulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
, thereby not only releasing the egg but also initiating the conversion of the residual follicle into a corpus luteumCorpus luteumThe corpus luteum is a temporary endocrine structure in mammals, involved in production of relatively high levels of progesterone and moderate levels of estradiol and inhibin A...
that, in turn, produces progesteroneProgesteroneProgesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
to prepare the endometriumEndometrium-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...
for a possible implantation. LH is necessary to maintain luteal function for the first two weeks. In case of a pregnancyPregnancyPregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
, luteal function will be further maintained by the action of hCG (a hormone very similar to LH) from the newly established pregnancy. LH supports theca cells in the ovary that provide androgenAndrogenAndrogen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
s and hormonal precursors for estradiol production.
- In the male, LH acts upon the Leydig cells of the testis and is responsible for the production of testosteroneTestosteroneTestosterone 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...
, an androgenAndrogenAndrogen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
that exerts both endocrine activity and intratesticular activity on spermatogenesisSpermatogenesisSpermatogenesis is the process by which male primary germ cells undergo division, and produce a number of cells termed spermatogonia, from which the primary spermatocytes are derived. Each primary spermatocyte divides into two secondary spermatocytes, and each secondary spermatocyte into two...
.
The release of LH at the pituitary gland is controlled by pulses of gonadotropin-releasing hormone
Gonadotropin-releasing hormone
Gonadotropin-releasing hormone , also known as Luteinizing-hormone-releasing hormone and luliberin, is a tropic peptide hormone responsible for the release of follicle-stimulating hormone and luteinizing hormone from the anterior pituitary. GnRH is synthesized and released from neurons within...
(GnRH) from the hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
. Those pulses, in turn, are subject to the estrogen feedback from the gonads.
Normal levels
LH levels are normally low during childhoodChildhood
Childhood is the age span ranging from birth to adolescence. In developmental psychology, childhood is divided up into the developmental stages of toddlerhood , early childhood , middle childhood , and adolescence .- Age ranges of childhood :The term childhood is non-specific and can imply a...
and, in women, high after menopause
Menopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
. As LH is secreted as pulses, it is necessary to follow its concentration over a sufficient period of time to get a proper information about its blood level.
During the reproductive years, typical levels are between 1-20 IU/L. Physiologic high LH levels are seen during the LH surge (v.s.); typically they last 48 hours.
Ovulation predictor kit (LH kit)
The detection of the Luteinising hormone surge indicates impending ovulationOvulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
. LH can be detected by urinary ovulation predictor kits (OPK, also LH-kit) that are performed, typically daily, around the time ovulation may be expected. The conversion from a negative to a positive reading would suggest that ovulation is about to occur within 24–48 hours, giving women two days to engage in sexual intercourse
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...
or artificial insemination
Artificial insemination
Artificial insemination, or AI, is the process by which sperm is placed into the reproductive tract of a female for the purpose of impregnating the female by using means other than sexual intercourse or natural insemination...
with the intentions of conceiving.
Tests may be read manually using a colour-change paper strip, or digitally with the assistance of reading electronics.
Tests for Luteinising hormone may be combined with testing for estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
in tests such as the Clearblue fertility monitor
Fertility monitor
A fertility monitor is an electronic device which may utilize various methods to assist the user with fertility awareness. A fertility monitor may analyze changes in hormone levels in urine, basal body temperature, electrical resistance of saliva and vaginal fluids, or a combination of these methods...
.
The sensitivity of LH tests are measured in milli international unit, with tests commonly available in the range 10-40 m.i.u.
As sperm can stay viable in the woman for several days, LH tests are not recommended for contraceptive practices, as the LH surge typically occurs after the beginning of the fertile window.
[note: photo shows "negative" results in the top strip, i.e., no LH surge, and "positive" results in the bottom strip. *This information needs editing. An LH surge will cause the test line (on the left) to be darker in colour than the strip on the right (depending on the brand you buy; follow package insert instructions for interpreting results). Women with PCOS may have LH in their urine throughout their cycle, causing their tests to appear coloured throughout the cycle as displayed in the bottom strip. ]
Relative elevations
In children with precocious pubertyPrecocious puberty
As a medical term, precocious puberty describes puberty occurring at an unusually early age. In most of these children, the process is normal in every respect except the unusually early age, and simply represents a variation of normal development. In a minority of children, the early development is...
of pituitary or central origin, LH and FSH levels may be in the reproductive range instead of the low levels typical for their age.
During the reproductive years, relatively elevated LH is frequently seen in patients with the polycystic ovary syndrome
Polycystic ovary syndrome
Polycystic ovary syndrome is one of the most common female endocrine disorders. PCOS is a complex, heterogeneous disorder of uncertain aetiology, but there is strong evidence that it can to a large degree be classified as a genetic disease....
; however, it would be unusual for them to have LH levels outside of the normal reproductive range.
High LH levels
Persistently high LH levels are indicative of situations where the normal restricting feedback from the gonad is absent, leading to a pituitary production of both LH and FSH. While this is typical in the menopause, it is abnormal in the reproductive years. There it may be a sign of:- Premature menopause
- Gonadal dysgenesisGonadal dysgenesisGonadal dysgenesis is a term used to describe multiple reproductive system development disorders. They are conditions of genetic origin. It is characterized by a progressive loss of primordial germ cells on the developing gonads of an embryo....
, Turner syndromeTurner syndromeTurner syndrome or Ullrich-Turner syndrome encompasses several conditions in human females, of which monosomy X is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent... - CastrationCastrationCastration is any action, surgical, chemical, or otherwise, by which a male loses the functions of the testicles or a female loses the functions of the ovaries.-Humans:...
- Swyer syndromeSwyer syndromeSwyer syndrome, or XY gonadal dysgenesis, is a type of hypogonadism in a person whose karyotype is 46,XY. The person is externally female with streak gonads, and left untreated, will not experience puberty...
- Polycystic Ovary SyndromePolycystic ovary syndromePolycystic ovary syndrome is one of the most common female endocrine disorders. PCOS is a complex, heterogeneous disorder of uncertain aetiology, but there is strong evidence that it can to a large degree be classified as a genetic disease....
- Certain forms of Congenital adrenal hyperplasiaCongenital adrenal hyperplasiaCongenital adrenal hyperplasia refers to any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the biochemical steps of production of cortisol from cholesterol by the adrenal glands ....
- Testicular failure
Deficient LH activity
Diminished secretion of LH can result in failure of gonadal function (hypogonadism). This condition is typically manifest in males as failure in production of normal numbers of sperm. In females, amenorrhea is commonly observed.Conditions with very low LH secretions are:
- Kallmann syndromeKallmann syndromeKallmann syndrome is a genetic disorder marked by anosmia and hypogonadism - the decreased functioning of the glands that produce sex hormones. Abnormalities in various genes may cause a defect in the hypothalamus, causing a deficiency of gonadotropin-releasing hormone ; this in turn causes...
- Hypothalamic suppression
- HypopituitarismHypopituitarismHypopituitarism is the decreased secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain...
- Eating disorderEating disorderEating disorders refer to a group of conditions defined by abnormal eating habits that may involve either insufficient or excessive food intake to the detriment of an individual's physical and mental health. Bulimia nervosa, anorexia nervosa, and binge eating disorder are the most common specific...
- Female athlete triadFemale athlete triadFemale Athlete Triad is a syndrome in which eating disorders , amenorrhoea/oligomenorrhoea and decreased bone mineral density are present. Also know simply as the Triad, this condition is seen in females participating in sports that emphasize leanness or low body weight...
- Hyperprolactinemia
- Gonadotropin deficiency
- Gonadal suppression therapy
- GnRH antagonist
- GnRH agonist (downregulation)
Availability
LH is available mixed with FSH in the form of Pergonal, and other forms of urinary gonadotropins . More purified forms of urinary gonadotropins may reduce the LH portion in relation to FSH. Recombinant LH is available as lutropin alfa (Luveris). All these medications have to be given parenterally. They are commonly used in infertility therapy to stimulate follicular development, the notable one being in IVF therapy.Often, hCG medication is used as an LH substitute because it activates the same receptor. Medically used hCG is derived from urine of pregnant women, is less costly, and has a longer half-life than LH.