(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.

(rFSH) Follicle stimulating hormone derived from genetic engineering instead of being extracted from the urine of postmenopausal women (human menopausal gonadotropin, or hMG) or from the pituitary glands of cadavers (human pituitary gonadotropin, or hPG). Produced and marketed by the two pharmaceutical companies Organon (as Puregon), or Fertinex in the US and Serono (as Gonal-F) to replace their hMG preparations. Has the advantage over hMG (and its purified derivatives) of being standard in biological structure and activity, and of not being of a human source (hPG -- but not hMG -- having been implicated in transmission of Creutzfeldt-Jakob disease).

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 follicle is "recruited" at two distinct stages of development. Early or continuous recruitment refers to the ongoing, continuous recruitment of primordial follicles to start their growth and become antral follicles, a process that is independent of major hormones, starts before birth and ends when there are no follicles left, this taking place around the time of menopause. Cyclical recruitment refers to the much later recruitment of medium-sized tertiary follicles into the ovarian cycle due to a temporary elevation of follicle stimulating hormone, which occurs at the end of each luteal phase, thus initiating a new follicular phase; the group of "recruits" susceptible to this late recruitment is called a cohort. Time-wise for a particular follicle, the two episodes of recruitment occur 8 months apart: in other words, it takes 8 months for a follicle to grow from its resting state before it can have a chance of making estrogen and then undergoing ovulation. Not all early-recruited follicles undergo later cyclical recruitment: some are lost through early atresia, many reach the stage at which they could be cyclically recruited at a stage when FSH is low (most stages of the ovarian cycle) and undergo atresia then. Readers will appreciate that ovulation induction, including intentional superovulation, can have no effect on the rate at which follicles are used up in ovaries or on the age at which menopause will occur (the different recruitment points involved are 8 months apart, with the early recruitment point governing the rate eggs are used up and the late recruitment point deciding how many follicles can respond to provide useable eggs.

Strictly, the process by which follicles are first formed in the ovaries before birth; in the woman, it means the growth of a primordial follicle into an early tertiary follicle -- a transition that confers receptiveness of the follicle to follicle stimulating hormone (FSH) The stimulus for initiation of follicular development and its timing for individual follicles remains a mystery.

Recombinant follicle stimulating hormone made by Organon. Called Puregon in Europe, Australia and Asia. On an equivalent dose basis, produces serum FSH that are somewhat slower to rise than with the use of hMG preparations, but which are ultimately higher: in other words, follicles and serum estradiol levels take a little longer to respond than they do to Humegon, but the number of mature, preovulatory follicles available for egg retrieval is the same or more. I find that 200 U (units) of Puregon per day produces a similar result to 225 U of Humegon or Metrodin. Generically known as follitropin beta.

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.

Recombinant follicle stimulating hormone made by Serono. Generically known as follitropin alpha.

One of the six main hormones that come from the front, glandular part of the pituitary gland, the adenohypophysis. A small amount is needed in the adults for follicle stimulating hormone to work properly. This led some doctors to add it injections of FSH in poor responders, but subsequent research has shown that increasing the amount of FSH does the same thing (and FSH is cheaper to buy than growth hormone).

Human recombinant follicle stimulating hormone.

(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.

Mixture of human menopausal gonadotropins containing follicle stimulating hormone made by Organon; virtually equivalent to Pergonal.

Absence of ovulation caused by insufficient GnRH drive from the hypothalamus, so that the pituitary gland doesn't produce enough follicle stimulating hormone. Usually accompanied by absent periods (amenorrhea).

Part of the brain lying immediately above (and connected to) the pituitary gland; responsible for producing gonadotropin releasing hormone and dopamine, among other hormones and substances (including the endorphins, serotonin, etc.). In women (when conditioned to cyclical function by a lack of exposure to male sex hormones before birth) it resonates with the ovarian cycle and cooperates with the pituitary gland to cause corresponding cyclical production of follicle stimulating hormone and, particularly, a timely LH surge. Responds to progesterone by raising the body's temperature

A protein hormone produced in women by developing follicles as well as by the corpus luteum, and in men by the testis in the presence of spermatogenesis, and acting on the pituitary gland to inhibit the production of follicle stimulating hormone. In women, falling levels occur as the number of developing follicles reduces to low numbers leading up to menopause, thus causing the elevation of serum FSH and shortening of the follicular phase that characterises the premenopause. In men, appreciable levels of serum inhibin B, a subclass of the inhibin family, predicts the presence of at least a small amount of sperm production.

(IUI) A form of assisted conception involving assisted insemination into the uterus, either for donor insemination (DI) or with husband's semen (AIH). IUI can be carried out with a woman's natural cycles or with ovarian stimulation (superovulation) using clomiphene or follicle stimulating hormone, with ovarian monitoring.

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.

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.

(OHSS) A complication of ovulation induction with, usually, follicle stimulating hormone, especially in cycles of superovulation for assisted conception, when it is intended to retrieve more than one egg. The ovaries become large, they can be painful, and there is excessive fluid released into the abdomen (the peritoneal cavity). Either removing this fluid or the occurrence of vomiting can cause dehydration, thickening of the blood and, occasionally, a serious thrombosis, such as a stroke. Death has been reported. Moderate to severe OHSS is treated in hospital, with administration of fluid intravenously, sometimes including albumin.

The use of drugs to stimulate the development of follicles in the ovaries to undergo ovulation, such as clomiphene, various preparations containing follicle stimulating hormone (FSH), and human chorionic gonadotropin (hCG). The two main situations for it are: in the treatment of infertility due to anovulation typically when there is oligomenorrhea or amenorrhea; and for superovulation in assisted conception (e.g. in vitro fertilisation and gamete intrafallopian transfer)

Mixture of human menopausal gonadotropins containing follicle stimulating hormone made by Serono; virtually equivalent to Humegon.

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.

Recombinant follicle stimulating hormone made by Organon. Called Follistim in the US. Generically known as follitropin beta.

Recombinant follicle stimulating hormone made by Organon. Called Follistim in US. On an equivalent dose basis, produces serum FSH that are somewhat slower to rise than with the use of hMG preparations, but which are ultimately higher: in other words, follicles and serum estradiol levels take a little longer to respond than they do to Humegon, but the number of mature, preovulatory follicles available for egg retrieval is the same or more. Professor Jansen, medical director of SIVF, notes that 200 U (units) of Puregon per day produces a similar result to 225 U of Humegon or Metrodin. Generically known as follitropin beta.

Measurement of follicle stimulating hormone in serum. Useful at the time of menstruation for indicating a significantly decreased number of eggs in the ovaries in the few years leading up to menopause (that is, indicative of depletion of eggs or primary ovarian failure); Continuously high in women after menopause, and then excreted in high amounts in the urine (from which, in turn human menopausal gonadotropin is derived).

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.

Intentional induction of multiple ovulations at once, using injections of follicle stimulating hormone and human chorionic gonadotropin, for assisted conception. Inevitably there is a risk of multiple pregnancy unless egg retrieval is performed.

The third stage of growth of the follicle, in which the egg is enclosed by a thick layer of round-shaped follicle cells among which an antrum, or fluid-filled space, has formed; this antrum will come to dominate the size of the follicle. The first stage of the follicle visible with transvaginal ultrasound (when it reaches about 4 mm in diameter). Further growth of the early tertiary follicle is determined by follicle stimulating hormone. Synonym: antral follicle.

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.