Role of Pituitary Gland in Fertility Preservation

Abstract

The pituitary gland is one of the major organs that make up the endocrine system. The pituitary gland secretes various hormones some of which acts on target organs specifically and some that act on other endocrine bodies to stimulate or inhibit production of hormones based on response to different signals in the body. The pituitary gland is also regulated by hormones released from the hypothalamus and hence, the hypothalamus and pituitary gland coalesce to form a central control unit for endocrine processes throughout the body. Of its numerous functions, the pituitary is very vital in reproduction as it regulates hormones that are necessary for reproductive functions in the body. This chapter discusses at length, the importance and role of the pituitary gland in reproduction. Basically, the pituitary gland responds to stimuli from the hypothalamus to produce hormones that act on the gonads (testes and ovaries) to produce sex hormones that are necessary for sexual maturation. The hypothalamus, pituitary gland and the gonads form a network for the communication via the hypothalamo-pituitary-gonadal axis and it allows efficiency in stimulating and inhibiting release of hormones via a feedback mechanism. The optimum functioning of the pituitary gland is absolutely necessary to facilitate a healthy reproductive functioning and avoid reproductive complications like infertility. Conception should be a natural part of life that should occur spontaneously and approximately 15–25% of couples within the reproductive age are struggling to conceive, and require medical attention to achieve this and only about 1–2% of couples are sterile. Infertility cases that result from pituitary gland-related complications can be caused by a number of factors either congenital or acquired. Recent research inferences on the pathophysiology of infertility have identified the overproduction of reactive oxygen species as an important factor in infertility. There are various studies regarding the effects of endocrine-disrupting chemicals (an environmental pollutant) on the reproductive functions of animals which can be through alterations in a hormonal milieu as well as reactive oxygen species. It therefore becomes imperative to look into effects of the environment on the endocrine pathways and its reflection on fertility. This chapter also looked into some of the causative factors of these disorders and the risk the pose to a reproductive health.

1. Introduction

The pituitary gland is a miniature endocrine organ that is situated at the base of the brain directly underneath the hypothalamus. It is suspended from the base of the brain by the infundibulum which is otherwise known as the pituitary stalk and it is situated within a small groove on the sphenoid bone. The pituitary gland is structurally and functionally considered as a double structure because it has 2 distinct parts—the anterior pituitary (adenohypophysis) and the posterior pituitary (neurohypophysis) which are of different embryonic origin and are specific in their own respective functions. The pituitary is sometimes referred to as the “master gland” because other than secreting its own hormones, it also controls secretion of hormones by other endocrine organs as responses to different signals in the body. The pituitary is capable of controlling all these other endocrine processes by forming a hypothalamo-pituitary complex which functions as central control for the brain to organize important processes in the body. The hypothalamo-pituitary complex controls these processes forming a circuit with target endocrine organs, these circuit is known as axis. This axis forms a kind of feedback loop which helps to stimulate or inhibit release of hormones from the hypothalamus and pituitary alike. The importance of the pituitary gland can be inferred by understanding the numerous functions that it serves in the body. Some of the functions of the pituitary gland include; regulation of body metabolism, growth and development, homeostasis and also reproduction. The pituitary is capable of exhibiting all of the aforementioned functions by actions of different hormones that it releases to different target organs in the body. Some of the hormones produced by the pituitary gland include growth hormone, thyroid-stimulating hormone, luteinizing hormone, follicle stimulating hormone, prolactin, oxytocin, etc. For the context of this chapter, there will be an emphasis on its importance in reproduction and fertility. The pituitary acts on the ovaries and testes through the hypothalamo-pituitary-gonadal axis and it controls the reproductive function in females and males through the actions of two hormones—luteinizing hormone and follicle stimulating hormone. In immediate pre-pubertal life, production of luteinizing hormone (LH) is usually in low quantities but as puberty begins to set in, LH production increases. This upsurge would cause the stimulation of gonadal steroidogenesis which is necessary for sexual maturation. In females, release of LH and follicle-stimulating hormone (FSH) which is triggered by the secretion of gonadotropin releasing hormone (GnRH), otherwise called luteinizing hormone releasing hormone (LHRH) from the hypothalamus helps to regulate the reproductive system. Once secreted, the LH and FSH act on the ovaries to stimulate ovulation and secretion of sex hormones which are estrogen and progesterone. Ovulation is made possible by summative action of the pituitary gland, the hypothalamus and the ovaries. As described earlier, the process kick starts in the hypothalamus which releases hormones that act on the pituitary gland to release gonadotropins (LH and FSH) which then acts directly on the ovaries. In the ovarian follicles, there are 3 types of cells; the theca, the granulosa and the oocyte. LH acts on the theca cells to produce androstenedione, FSH then stimulates aromatase to act on the androstenedione to produce estradiol. Once estradiol is produced, it causes a positive feedback on LH release by blocking off negative feedback that is caused by estrogen. The further release of LH would then cause an “LH surge,” which would in turn initiate the ovulation process. After the event of ovulation, the ovarian follicle turns into the corpus luteum. The corpus luteum is responsible for secretion of progesterone and human chorionic gonadotropin in the event of a pregnancy. In males, the release of FSH and LH by the pituitary gland is responsible for spermatogenesis—production of sperm and the secretion of testosterone, the male sex hormone.

2. Factors that can affect normal functioning of the pituitary gland

It is important that there is a balance in the level of hormones that is being produced by the pituitary gland to allow proper functioning of the reproductive systems. Hormonal imbalances resulting from incompetence of the pituitary gland can have huge ramifications on the reproductive systems and ultimately resulting in fertility complications. Several factors can be held responsible for improper functioning of the pituitary gland, some of these factors are;

• Tumors: Pituitary tumors (also known as pituitary adenomas) are slow-growing non-cancerous growths on the pituitary gland. These tumors are categorized into two; non-functioning adenomas (or non-secreting) and functioning adenomas (or secreting). The non-functioning adenomas do not secrete any hormones but can grow uncontrollably large which might require surgical removal and in rare cases, the tumor can rupture and result in internal hemorrhage. The functioning adenomas usually secrete hormones which can directly cause hormonal imbalances that would result in infertility. The functioning adenomas are classified based on the hormones they secrete. A very common type of a functioning adenoma is the prolactinoma, which causes excess release of prolactin. It is responsible for about 40% of all the pituitary tumors and its occurrence is more prevalent in the female populace [1] and also about 15% of total intracranial tumors [2]. Excess production of prolactin (hyperprolactinemia) can cause a range of complications in the reproductive system. Excess prolactin suppresses the action of FSH and LH which causes irregularities in the menstrual cycle and also interferes with ovulation in women and cause inability to conceive in women. It can also cause a condition known as “galactorrhea” which means production of breast milk in women who are not breastfeeding or even pregnant. In men, suppressed action of FSH and LH can impede spermatogenesis and cause impotence. It can also cause low sex drive in both sexes.

• Trauma: Physical infarctions to the pituitary gland resulting from head injuries such as skull fractures or concussions can damage the gland and stop its functioning which would result in hormonal imbalances which in turn translates to infertility. Some other symptoms that might result from trauma to the pituitary gland include fatigue, headaches and vision problems.

• Auto-immune diseases: Diseases like hypophysitis where the body defenses attack the pituitary gland and cause inflammation and damage to the gland. This can also lead to hormonal imbalances and cause fertility problems.

• Infections: Some infections like meningitis and tuberculosis can affect the functioning of the pituitary gland. The causative bacteria of tuberculosis “mycobacterium tuberculosis” which majorly infects the lungs is also capable of affecting other parts of the body including the pituitary gland. Its malfunctioning can result when the bacteria affects the pituitary gland, a condition called tuberculous hypophysitis of the pituitary gland.

• Medications such as antidepressants, antipsychotics and chemotherapy drugs can affect the normal functioning of the pituitary gland and cause hormonal imbalances.

• Radiation therapy: Radiation exposure to the skull for treatment of intracranial malignancies alter the proper functioning of the pituitary gland.

All the aforementioned factors can affect the pituitary gland and lead to hormonal imbalances by either causing over activity or under activity of the gland. These conditions are known as hyperpituitarism and hypopituitarism respectively.

3. Effects of pituitary gland dysfunction on reproduction and fertility

3.1 Hyperpituitarism

Hyperpituitarism, a condition where there is excessive secretion of pituitary hormones can be largely associated with functional pituitary adenomas which can stimulate excess hormone secretion (e.g. prolactinoma). The complications that result from this however depends on the particular hormone that is being over secreted. The most commonly affected hormones in hyperpituitarism are growth hormone and prolactin. Although both hormones are not directly involved with fertility, prolactin is an important hormone for secondary sexual characters which includes breast development and production of milk in pregnant and lactating mothers. Also, excess prolactin can suppress the production of estrogen and testosterone which influences fertility by causing anovulation in females and decreased sperm production and quality in males. Hyperpituitarism is mostly treated using medication regimen, however the approach to managing the condition may depend on the cause and severity. Other ways of managing hyperpituitarism are the surgical approach and radiotherapy.

3.2 Hypopituitarism

Hypopituitarism is a condition where the pituitary gland cannot produce hormones in the required amounts for proper functioning. Hypopituitarism is the absolute or partial loss of the pituitary gland (anterior and posterior) function that can result from hypothalamic or pituitary disorders [3]. It is less prevalent in comparison to hyperpituitarism. Also, some other contributing factors like the cause of the hypopituitarism, the age of onset and the severity of the hormone deficiency can affect the clinical presentation of the clinical state. Depending on the etiology of the hypopituitarism, the condition can be categorized into two groups—primary and secondary hypopituitarism.

3.2.1 Primary hypopituitarism

In primary hypopituitarism, the condition is caused by disorders of the pituitary gland which can be caused by damage or inadequate functioning of the pituitary hormone secreting cells. Other causes of this condition are tumors (pituitary adenomas), surgical complications and exposure to radiation in therapy. In cases related with adenomas, the onset of the condition is usually slow. However, in patients who suffer from pituitary hemorrhage or lack of blood supply to the pituitary gland, a medical condition referred to as pituitary apoplexy, the onset of the hypopituitarism is normally quick and symptoms may begin to prevail within hours. This is as seen in postpartum hemorrhage or in trauma where the blood loss is massive and replacement wasn’t commensurate with the loss.

3.2.2 Secondary hypopituitarism

In secondary hypopituitarism, the condition is associated with complication with the hypothalamus. This could be from damage to the infundibulum (pituitary stalk) which is often caused by trauma to the head or neck. Also tumor growth in proximity of the sella turcica if big enough, can exert pressure on the pituitary stalk and cause a lesion. In surgical attempts to remove such types of tumor (sellar or parasellar tumors), the pituitary stalk is highly exposed and is at a great risk of being damaged and this can lead to secondary hypopituitarism.

Like hyperpituitarism, the clinical presentation largely depends on the specific pituitary hormone that is being under-produced. In regards to reproduction and fertility, the gonadotropins are the major hormones of concern. However, symptoms and clinical presentation of low gonadotropins depends on the stage of onset (pre-pubertal or post puberty). Some of the symptoms are listed below;

• Exaggerated decrease in size of penis and absence of testicles.

• Lack of development of secondary sexual features during puberty (e.g. breasts and pubic hair).

• Low sex drive and desire in adulthood.

• Fertility complications in adulthood.

3.3 Pituitary hyperplasia

This is associated with a rapid increase in the number of one or more cell subtypes of the pituitary gland. These increments are characterized by an enlargement of the pituitary gland. It can occur as a result of physiological or pathological changes in the body. Pregnancy state is a period where there are numerous physiological changes in the body. During pregnancy, the pituitary gland increases in weight and size by almost one-third of its original size. This inflammation is caused by activation of lactotroph cells which in turn causes stimulation of prolactin [4]. Prolactin stimulation helps preparing the mother for lactation and breastfeeding. Although, the condition is reversible in the normal physiological conditions like pregnancy, other inflammations resulting from pathological effects may require medical intervention for their management.

4. The hypothalamo-pituitary gonadal axis and its role in reproduction

The hypothalamo-pituitary-gonadal axis (HPG axis) is a complex system that is in charge of controlling and regulation of hormones that are persistent with reproductive function and fertility in both males and females. As stated earlier, a typical hypothalamo-pituitary axis consists of the hypothalamus, the pituitary gland and the target organs terminally. The target organs of the HPG axis are the gonads, which are specifically the ovaries and testes in males and females respectively. The first component, the hypothalamus, is a small organ that is located deep within the center of the brain and directly above the pituitary gland—the pituitary gland is suspended from the hypothalamus by the pituitary stalk. The hypothalamus is a vital organ for regulating numerous physiological functions in the body one of which is the regulation of release of pituitary hormones. However, the hypothalamus is also capable of secreting its own hormones, the hormones released by the hypothalamus are widely categorized into two; tropic hormones which are hormones that act directly on different target organs in the body, and hypophysiotropic hormones which are released to act on the pituitary gland. The hypothalamus is largely connected with different parts of the central nervous system (CNS) but it is however most closely related and connected to the pituitary gland due to their interwoven actions and their close proximity to each other. This tightly connected formation gives rise to the hypothalamo-pituitary complex. This complex then forms an axis by terminally connecting to different target organs. These axes include hypothalamo-pituitary gonadal (HPG) axis, hypothalamo-pituitary-adrenal axis, hypothalamo-pituitary-thyroid axis and also the growth hormone axis. The HPG axis serves a variety of functions in the body which includes development of the immune system, aging but most importantly reproduction. The mechanism of action of the HPG axis begins at the hypothalamus by releasing gonadotropin-releasing hormones (GnRH) which is an example of hypophysiotropic hormone because it acts directly on the pituitary gland to release gonadotropins. The released gonadotropins (LH and FSH) then acts on the gonads (testes and ovaries) in their own distinct ways which has been explained earlier in this chapter. The HPG axis has distinct actions in both males and females and are also regulated differently by their own respective negative feedback mechanisms which regulates the stimulation and inhibition of release of hormones by the hypothalamus and pituitary gland (Figure 1).

Figure 1.

Diagram showing the dynamic of the hypothalamo-pituitary-gonadal axis [5].

In males, the production of the male sex hormone (testosterone) and also the male gamete (sperm cells) are the primary responsibility of the HPG axis. Production of testosterone is achieved by the bonding of luteinizing hormone (LH) to the interstitial cells of the testes and stimulating the Leydig cells to synthesize it [6]. Spermatogenesis, on the other hand, is stimulated by the follicle-stimulating hormone (FSH). FSH stimulates Sertoli cells which are present in the seminiferous epithelium. The stimulated cells produce a protein complex called the androgen-binding protein (ABP). The ABP synergizes with the already-produced testosterone to provide regulatory molecules and nutrient materials required for maintaining spermatogenesis. Therefore, both the FSH directly and LH indirectly regulate spermatogenesis through the bonding of ABP to testosterone. The HPG axis in males is regulated by a negative feedback effect on the hypothalamus by inhibiting the release of GnRH which in turn halts the release of FSH and LH. The negative feedback is achieved by the release of inhibin by the Sertoli cells which inhibits another protein activin that stimulates the release of gonadotropins by the pituitary gland and hereby indirectly inhibiting the hypothalamus (Figure 2).

Figure 2.

Diagram showing the feedback loop of the hypothalamo-pituitary-gonadal axis in males [7].

In females, the HPG axis is primarily concerned with the regulation of the ovarian cycle and the menstrual cycle. As the gonadotropins are released by the pituitary gland, they stimulate the production of estrogen and inhibin by the ovary. Like testosterone in males, estrogen directly inhibits the release of GnRH by the hypothalamus through a negative feedback mechanism. Inhibin here also suppresses activin which indirectly inhibits the hypothalamic release of GnRH. In the reproductive cycle, the development of the ovarian follicle is achieved by a positive feedback loop that involves LH and estrogen. Once the developed follicle releases its ova, there is stimulation of the ovary to produce progesterone. Production of progesterone provides a negative feedback effect that counters the positive feedback of LH and estrogen, and this feedback suppresses the production of GnRH by the hypothalamus which in turn inhibits the release of gonadotropins from the pituitary. In the other event that the follicle is not fertilized and the onset of menstruation begins, the level of progesterone diminishes and the negative feedback is also overturned which now allows the production of GnRH from the hypothalamus and also the release of the gonadotropins from the pituitary. The released gonadotropins now begin to prepare the next ovarian follicle for the reproductive cycle. The HPG axis is also responsible in the menstrual cycle as the hormones produced by the pituitary are involved in the three phases of the menstrual cycle (Figure 3).

Figure 3.

Diagram showing the feedback loop of the hypothalamo-pituitary-gonadal axis in females [8].

The HPG axis is a somewhat complex system that ensures the regulation of hormones that control reproductive functions and fertility. Being an essential benchmark in the endocrine system, its proper functioning is important for reproductive competence and fertility. The HPG axis is closely controlled by various feedback mechanisms that ensure hormones are produced in adequate quantities and at the right time. Any disruption in the normal functioning of the HPG axis is tantamount to having significant ramifications for the reproductive system and fertility which can culminate in reproductive disturbances.

4.1 Disorders of the hypothalamo-pituitary-gonadal axis and their implications on reproduction and fertility

The HPG axis can be affected at any level of its organization (i.e. it can occur at the hypothalamus, pituitary gland and also at the gonads in both sexes), and this can translate to different implications. Although the cause of some of these disorders are generally considered idiopathic, some contributory factors include:

• Genetics: Some of the disorders of the HPG axis are as a result of genetic abnormalities. HPG axis disorders like Klinefelter and Turner syndrome in males and females respectively are as a result of genetic aberrations on the chromosomes.

• Trauma: An injury or physical lesions to the brain or the gonads can disrupt the normal functioning of the HPG axis and can ultimately lead to hormonal imbalances.

• Autoimmune diseases: Such diseases affecting the immune system can affect the ovaries and testes causing interference with the axis thereby causing imbalances.

• Tumors: Abnormal growth(s) can disrupt by stimulating or inhibiting production of hormones.

• Medications: Drugs such as chemotherapy can disrupt hormone production and lead to HPG disorders.

• Environment: Exposure to some environmental elements like chemicals and radiation can interfere with the HPG axis and cause hormonal imbalances. Also environmental toxins like Bisphenol-A (BPA) which is an established endocrine disruptor can directly cause hormonal alterations which can lead to HPG axis disorders.

Some of the disorders that can result from the disruption of the HPG axis include hypogonadism which is a condition whereby the gonads produce little or no sex hormones which will lead to a range of symptoms that are all associated with infertility. Prepubertal affectations can lead to precocious puberty, a condition where there is an abnormal haste or delay in the onset of puberty in the adolescents. Kallmans syndrome is also a genetic disorder which causes failure of puberty due to lack of production of gonadotropin-releasing hormone in the hypothalamus. However, there are more sex-specific disorders that can be caused by the disruption of the HPG axis.

4.2 Effect of environmental toxins (endocrine disruptors) on the pituitary gland and fertility

Over the past decade, studies on the effects of Endocrine Disrupting Chemicals (EDCs) on the reproductive functions of animals have raised some health concerns. In response to these concerns, the World Health Organization (WHO) has several publications, including the recent state of the science of endocrine disrupting chemicals in 2012 [9]. Worldwide, urbanization is progressing with increased demands and use of BPA. It is currently being used in many of our day to day materials such as foods packages, papers, electronics, medical equipments, etc. Therefore, there will be an upsurge in the possible health risks associated with endocrine disrupting chemical exposures. One of such EDC is Bisphenol-A (BPA).

Bisphenol-A is a synthetic chemical that is used in the manufacturing and production of polycarbonates and epoxy resins [10]. These (polycarbonates and epoxy resins) are two types of thermosetting plastics that are widely used in various applications like production of some day-to-day materials for human usage. Some of these materials include; food containers, water bottles, eyeglass lenses and in electronics. Hence, BPA is a very popular chemical compound in our environment. In recent times, a high number of chemicals with endocrine-disrupting abilities have been recorded and they are generally referred to as endocrine-disrupting chemicals (EDCs) [11]. EDCs are exogenous substances that are able to simulate or interfere with the endocrine system hereby remodifying important biological processes like organ development, reproduction, metabolism, etc. [12]. BPA is one of the most common EDCs and it can mimic the action of estrogen and can cause alterations in the endocrine systems which can cause adverse effects on the human reproductive health [13, 14].

Laboratory studies have shown that fetal and neonatal exposure to relatively low doses of BPA may result in reproductive and developmental disorders, including impaired sexual differentiation in the brain [15]. The accumulation of BPA deposits also has clinical implications on the reproductive system since exposure to its low doses during prenatal life has been shown to affect spermatogenesis in the offspring of male rodents. Sex specific changes in the function of infant’s hypothalamo-pituitary-adrenal axis, which may culminate in anxiety or depression-like behaviors in offspring, can be associated with prenatal exposure to BPA [16].

By mimicking the action of estrogen, BPA can cause some modifications such as benign lesions, endometrial hyperplasia, development of ovarian cysts and increase in the ductile density of the mammary glands. Regarding the pituitary gland functions, BPA disrupts the production and secretion of gonadotropin-releasing hormones (GnRH) from the hypothalamus and this in turn would also affect the production of the gonadotropins (LH and FSH) from the pituitary gland. Due to the importance of gonadotropins on the function of the gonads, any disruption in their activity can compromise fertility and reproductive health. The reproductive complications of BPA are expressed differently in males and females. In an animal study carried out by [17], where they administered different doses of BPA to male rats at infant and adolescent stages. The results showed that BPA exposure at these stages caused histological alterations and also reduced sperm cells quality and quantity at both stages. Also, there was noticeable alterations in the levels of the sex hormones as levels of LH and FSH were elevated as well as the testosterone levels. Gupta et al. [18] also reviewed studies about BPA exposure and infertility in men. The underlying mechanism of BPA induced pathology is believed to be disruption in the steroidogenesis pathway and increased oxidative stress [19]. There was decreased sperm quality and motility in exposed. Also, low sperm counts, abnormal sperm morphology and elevated FSH levels were shown in a similar study [18]. The ability of BPA to mimic estrogen sometimes allows it to bind to estrogen receptors in the brain and this would lead to alterations in the feedback system which can disrupt the release of hormones. However, in the hypothalamo-pituitary-ovarian axis, it causes a series of changes that develop into symptoms that are related to infertility. This has been proven by both animal and human studies. In animal studies carried out by [20], they examined the effect of BPA exposure in adolescent rats and their experiments revealed that exposure of these newborn rats caused some alteration in their hormone profile as well as some histological changes that were peculiar with a common endocrine disorder in women known as polycystic ovarian syndrome (PCOS). It was noticed that the serum level of FSH and LH were elevated, this is a hallmark of PCOS in females. Also there was presence of multiple defective follicles in the histomorphometry of the ovaries. This observation was also made by [21] on the effects of BPA on ovaries of exposed rats. These degenerative changes were caused by BPA’s interference with folliculogenesis. Also in reference to PCOS, another major symptom which is hyperandrogenism was noticed in the serum analysis of the exposed rats as the level of testosterone was markedly increased. In human studies, there was reported irregularities in the menstrual cycle and also the development of PCOS which could both lead to infertility [18]. Due to the sensitivity of the female menstrual cycle and fertility to hormonal imbalances and alteration in endocrine function, it can be established that BPA and other endocrine disruptors can have an adverse effect on the reproductive health of individuals. Whilst BPA is very common in our environment nowadays, it is imperative that some lifestyle amendments are made to reduce interaction and exposure to BPA such as:

• The use of BPA-free products: People should actively look out for “BPA-free” labeled products when shopping for water bottles, food containers and other plastic products that may contain BPA.

• Eating fresh foods: Materials used in processing and packaging processed food may be containing BPA and instead people should opt for fresh foods, frozen foods and vegetables.

• Using glass or stainless steel containers for food storage instead of plastics.

• Avoiding thermal paper receipts whenever possible because they are often BPA-coated.

4.2.1 Polycystic ovarian syndrome

In females, a major disorder of the HPG axis is polycystic ovarian syndrome (PCOS). It is the most common endocrine disorder that occurs in women of reproductive age, affecting a reported 6–10% of adolescents and adult women [22]. PCOS is characterized by the development of multiple cysts on the ovaries and is accompanied by some hallmark symptoms like menstrual cycle abnormalities and hyperandrogenemia (abnormally high level of male sex hormones). LH stimulates the theca cells in the ovaries to produce androgens, these androgens are converted into estrogen by the action of an enzyme known as aromatase. In HPG dysfunction, the androgen is not converted into estrogen and this leads to the hyperandrogenemia. This leads to an array of symptoms that include hirsutism, acne, polycystic ovaries and usually menstrual abnormalities with infertility. Our study has shown that environmental toxins such as bisphenol-A causes hyperandrogenaemia, as shown by increase in the luteinizing hormone of the pituitary and consequently in the testosterone level. These hyperandrogenic states demonstrated poses risks similar to those seen in PCOS states, which can result in anovulation and consequent conception difficulties.

5. Conclusion

The importance of the pituitary gland in fertility preservation and reproduction cannot be understated because it secretes the hormones that stimulate the gonads to produce the sex hormones required for reproduction. The gonadotropins secreted by the pituitary are also necessary for sex cell development, i.e. spermatogenesis and oogenesis. Deficiencies of the pituitary gland and HPG axis that are concerned with hormone imbalances can be as a result of insufficiency of the specific organ (testes or ovary) or problems from the hypothalamus or pituitary gland that affect these organs. These disorders are majorly attributed to insufficient or excessive hormones resulting in complication such as infertility. Diagnosis of these disorders includes measuring the basal hormone levels in the serum. These disorders can be managed through means of medications, hormone replacement therapy or even surgery depending on the severity it poses. Recent upsurge in exposure to endocrine disrupting chemicals (Bisphenol-A inclusive) will in future culminate into increased incidence of pituitary reproductive hormonal imbalances, thereby distorting the gonadal milieu with concurrent rise in fertility issues.