(LH) The hormone, or gonadotropin, produced by the pituitary gland to cause, in women, ovulation of a mature follicle in the ovary, resulting in formation of the corpus luteum; in men, stimulates the production of testosterone by the Leydig cells of the testis. Suppressed by GnRH-agonists and GnRH-antagonists, so that (for ovulation induction) an injection of human chorionic gonadotropin (hCG), which acts the same way, has a predictable time course of action. A small amount of LH is essential for normal function of the tertiary follicle and the corpus luteum. Recombinant LH is under development by Serono as Luveris, but its clinical role in place of hCG is not yet established.

(rLH) luteinising hormone derived from genetic engineering technology instead of being extracted from the urine. Marketed by Serono as Luveris.

The glandular part of the pituitary gland, lying toward the front, so in medical speak called the anterior pituitary. Produces follicle stimulating hormone, luteinising hormone and prolactin. Other hormones include hormones that: (1) cause normal childhood growth (growth hormone), (2) drive the thyroid gland (thyroid stimulating hormone, or TSH), and (3) drive the adrenal gland (adrenocorticotropic hormone, or ACTH). See also hypothalamus and neurohypophysis.

A GnRH-antagonist made by Serono. Approved for women undergoing in vitro fertilisation), with good results when started on day 7 of the cycle, after 5 or 6 days' Gonal-F in suppressing the LH surge; the dosage, however, appears to be critical, to avoid over-suppressing natural luteinising hormone. Marketed as Cetrotide.

A gonadotropin produced by the trophoblast of the placenta that acts like luteinising hormone.

Latin for yellow body, the description being that of the solid or cystic structure in the ovary after ovulation. Derived from the ovulating Graafian follicle. At first red and friable as arteries and veins invade the collapsed follicle, it soon matures into a gland that is very efficient at producing progesterone, a hormone that's soluble in the fat and which therefore gives the corpus luteum its yellow color. Provides its name to the second, or luteal phase of the ovarian cycle, as well as to luteinising hormone, which causes the corpus luteum to be formed and sustains it until, in the event of pregnancy, it is supported instead by human chorionic gonadotropin. The appearance of the corpus luteum on transvaginal ultrasound is so variable (and so able to be confused with a serious abnormality of the ovary) that for accurate diagnosis of such pathology it is best to scan in the follicular phase or while taking a progestogen to prevent formation of this structure. Plural: corpora lutea.

Highly purified Metrodin, with no residual luteinising hormone, thus equivalent in activity to recombinant FSH. Called Metrodin HP outside the US. Made by Serono.

(FSH) The hormone, or gonadotropin, produced by the pituitary gland that in women stimulates the tertiary follicle to grow; in men it stimulates spermatogenesis. Obtained from human sources in a mixture with luteinising hormone (LH) as (1) human menopausal gonadotropin (hMG), extracted from the urine of women who have been through the menopause (Humegon, Metrodin and Pergonal); and (2) human pituitary gonadotropin (hPG), from human pituitary glands removed at autopsies (now obsolete). Today, pure FSH is made synthetically with gene technology (recombinant FSH), such as Gonal-F and Puregon.

A GnRH-antagonist made by Organon. The first to be FDA approved for women undergoing in vitro fertilisation), with good results when started on day 7 of the cycle, after 5 or 6 days FSH in suppressing the LH surge; the dosage, however, appears to be critical, to avoid over-suppressing natural luteinising hormone. Marketed as Antagon in the US and as Orgalutran elsewhere.

A GnRH-analog that briefly stimulates the pituitary gland to release follicle stimulating hormone (FSH) and luteinising hormone (LH), but then within a few days reduces these hormones to low levels (you could say that the pituitary has had a clamp put on it), stopping these hormones from competing with administered hormones -- and, particularly in women, suppressing the LH surge that otherwise can spoil the timing of egg retrieval in an assisted conception program such as IVF or GIFT. Examples include: leuprorelin(Lucrin, made by Abbott, used in Australia and Europe) or leuprolide (Lupron, made by Abbott in the US); nafarelin (Synarel, by Syntex); goserelin (Zoladex, by ICI); triptorelin (Decapeptyl, by Ipsen Biotech and used in Europe) and buserelin (Suprefact, by Hoechst, used in Europe).

A GnRH-analog that (unlike GnRH-agonists) immediately stops the pituitary gland from releasing the gonadotropins follicle stimulating hormone (FSH) and luteinising hormone (LH). Can substitute for GnRH-agonists for many gynecological purposes (particularly to suppress the LH-surge in assisted conception), although its use with pure FSH preparations (such as Fertinex, Gonal-F, Metrodin HP or Puregon) can lead to poor egg quality unless the dosage is carefully controlled or some luteinising hormone is added to the stimulation regimen.

Any hormone that switches on the function of the gonads. There are two main families of gonadotropins: (a) the gonadotropin that stimulates the growth of the follicle, or follicle stimulating hormone (FSH); and (b) those that cause ovulation from the mature follicle and stimulate the corpus luteum that results to develop and to produce progesterone, namely luteinising hormone (LH) and human chorionic gonadotropin (hCG). FSH will cause growing follicles to produce the estrogen estradiol, provided that a small amount of LH (or hCG) is present. FSH and LH are produced in the pituitary gland, whereas hCG comes from the placenta in pregnancy. In men, FSH stimulates the Sertoli cells of the testicular tubules, and hence drives spermatogenesis; LH and hCG stimulate the Leydig cells to produce testosterone.

A hormone produced by the hypothalamus of the brain to regulate production and release of the gonadotropins follicle stimulating hormone and luteinising hormone. Can be administered to induce ovulation when it is deficient (particularly in amenorrhea due to weight loss or excessive exercise), but it has to be given in small amounts directly into a vein, every 60 to 90 minutes for the two weeks of a normal follicular phase (with an electronic syringe-driver), mimicking its natural pattern of secretion.

(hCG) A gonadotropin produced by the placenta in pregnancy (specifically it's produced by the trophoblast of the chorionic villi); the hormone measured in performing a pregnancy test. The generic (no frills') name for Pregnyl and Profasi, which are preparations of hCG obtained by extracting it from the urine of pregnant women, and Ovidrel, which is made by recombinant gene technology. Mimics the action of luteinising hormone (LH), but has a very much longer duration of action -- and this gives hCG considerable advantages over LH in clinical use. Given as an injection to lead to ovulation from a mature follicle 38 hours after the injection; or to stimulate ongoing function of the corpus luteum, particularly its production of progesterone. So it is typically given after a course of follicle stimulating hormone (FSH) in assisted conception (IVF or GIFT) programs and ovulation induction programs 36 hours before the expected time of egg retrieval (or before having sex or IUI), and then sometimes in further, smaller doses to support the luteal phase that follows. Sometimes used with clomiphene. Ovarian monitoring is needed for its correct use with FSH or with clomiphene. hCG treatment can precipitate the ovarian hyperstimulation syndrome (OHSS).

(hMG) A mixture of follicle stimulating hormone (FSH) and luteinising hormone (LH) extracted for therapeutic use from the urine of menopausal women (women after the menopause normally produce these hormones in high concentration). Marketed as Humegon (Organon) and Pergonal (Serono). Metrodin (Serono) is hMG from which LH has been removed, and Metrodin HP (Serono) is Metrodin from which other urinary proteins have been removed too, resulting in very pure FSH. Ferring market a highly purified hMG containing both FSH and LH, but not in Australia (see Menogon or Repronex). No cases of transmitted (infectious) disease have been recorded after the use of hMG preparations, unlike human pituitary gonadotropin.

(hPG) A mixture of follicle stimulating hormone (FSH) and luteinising hormone (LH) extracted directly from pituitary glands obtained at autopsies; not used in Australia or elsewhere since 1986, when it was shown that Creutzfeldt-Jakob disease (CJD), a deadly form of dementia, had been transmitted from its use, presumably due to contaminating and infected brain tissue. Before 1986 it had been used mostly for ovulation induction in women with amenorrhea (absent periods) for which other hormones or drugs had not been effective, although sporadic instances of its use for in vitro fertilisation are known in Australia. No new cases of CJD have been reported among former users of hPG since the early 1990s.

Cells of the testis lying between the testicular tubules in which sperm are formed (hence their other name, interstitial cells), and responsible for the production of the male sex hormone testosterone under the influence of luteinising hormone.

A sudden and huge increase in production of luteinising hormone by the pituitary gland in response to sustained and substantial levels of estradiol in the blood in women, midway through the ovarian cycle. Causes ovulation about 36 hours after it starts (about 20 hours after its peak). If not suppressed during assisted conception (see GnRH-agonists and GnRH-antagonists) it can start before human chorionic gonadotropin has been given, so spoiling the timing of egg retrieval. Timely production of the LH surge in adult women depends on female conditioning of the hypothalamus and/or the pituitary gland before birth. Detectable by testing the urine with a special kit.

A treatment protocol for using GnRH-agonists that involves their use for more than a week before injections of follicle stimulating hormone (FSH) start for induction of superovulation in assisted conception programs. The advantage is that any temporary rise in luteinising hormone levels and progesterone levels has dissipated before the development is under way of those ovarian follicles from which eggs will be obtained at egg retrieval. The disadvantage, compared with the short protocol, is that higher (hence more expensive) doses of GnRH-agonist and FSH are needed. The GnRH can be started with menstruation or during the luteal phase of the previous cycle.

Generic name for recombinant luteinising hormone.

Recombinant luteinising hormone (LH) made by Serono.

Human menopausal gonadotropin (hMG) from which luteinising hormone (LH) has largely been removed, leaving follicle stimulating hormone (FSH) as the active substance. Metrodin HP (Fertinex in the US) is more purified, other urinary proteins having been extracted too, and (unlike Metrodin) has no LH activity at all. Made by Serono.

Called Fertinex in the US. Metrodin that has been highly purified by removing all contaminating urinary proteins and all luteinising hormone, and is thus similar in action to recombinant follicle stimulating hormone.

Gland located at the base of the brain and responsible (among other jobs) for driving the ovaries in women and the testes in men by way of the pituitary hormones follicle stimulating hormone (FSH) and luteinising hormone (LH), which are under the influence of gonadotropin releasing hormone (GnRH) from the hypothalamus. Composed of two parts, the adenohypophysis, or truly glandular part, in front, and the neurohypophysis, which is a down-growth of the brain, behind.

Measurement of luteinising hormone in blood serum. Used in monitoring to judge the occurrence of the LH surge, if GnRH-analogs have not been employed. The result should be available within 4 hours of the test for this purpose.

A treatment protocol for controlled stimulation of the ovaries using GnRH-agonists with injections of follicle stimulating hormone (FSH) for induction of superovulation in assisted conception programs involves starting the GnRH-agonist a day or two before the injections of FSH start. The advantage is one of cost: less FSH (and less GnRH-agonist) are used compared with the long protocol. The disadvantage is that luteinising hormone levels and progesterone levels can rise, possibly (in some cycles of treatment) spoiling optimal development of ovarian follicles. The GnRH-agonist is continued (in contrast to the ultrashort protocol) until follicles are mature and human chorionic gonadotropin is given to start the process of ovulation.

A layer of cells in the ovary lying immediately around the follicle; under the influence of luteinising hormone it's responsible for producing the weak male sex hormone androstenedione, which is then (1) converted by the follicle cells (the granulosa cells) into estrogen, principally estradiol, or (2) converted by other tissues outside the ovary to testosterone.

A variation of the short protocol for using GnRH-agonists with injections of follicle stimulating hormone (FSH) for controlled induction of superovulation in assisted conception programs. The GnRH-agonist is started with menstruation, a day or two before the injections of FSH start, and is discontinued after about 5 days from starting it (i.e. often a week or more before ovulation). There are no special advantages, whereas there's a potential disadvantage: a much more thorough suppression of the woman's own luteinising hormone (and maybe FSH) than if the GnRH-agonist is continued -- potentially causing stimulated follicles to 'run out of puff' before they are fully mature. The ultrashort protocol should not be used with pure forms of FSH, such as Fertinex, Gonal-F, Metrodin HP or Puregon, or poor egg quality will result if some luteinising hormone is not administered.

A home test for ovulation in which the urine is tested for luteinising hormone. If the urine shows a positive test, ovulation will usually take place within 24 to 36 hours. Electronic devices that perform the same function are available (and are increasingly popular in the U.K.).