2. TABLE OF CONTENT Introduction of Pituitary Gland. Origin and location of Pituitary Gland. Anatomy and Histology of the Pituitary Gland Structure of Pituitary Gland. Parts of Pituitary Gland. Hormones sereted from Pituitary Gland. Diseases found in Pituitary Gland. Diagrams Functions of Pituitary Gland. Conclusion.
3.
4. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica) covered by a dural fold (diaphragm sellae).
5. The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoid bone in the middle cranial fossa at the base of the brain.
6. The pituitary gland secretes hormones regulating homeostasis, including tropic hormones that stimulate other endocrine glands.
7. It is functionally connected to the hypothalamus by the median eminence via a small tube called the Pituitary Stalk.
8.
9. Anatomy and physiology of the pituitary gland: The pituitary gland weighs about 0.5 to 1 g and is divided into anterior and posterior lobes. The pituitary gland sits in the sella turcica immediately behind the sphenoid sinus. Cavernous sinuses are located laterally on each side of the sella, inclusive of the internal carotid artery and cranial nerves III, IV, V1, V2 and VI. Magnetic resonance imaging (MRI) is the best method for the visualization of hypothalamic-pituitary anatomy, because the optic chiasm, vascular structures, and tumor extension to cavernous sinuses can be well visualized compared with other imaging techniques Anterior pituitary hormones are regulated by hypothalamic releasing and inhibitory hormones and negative feedback action of the target glandular hormones at the pituitary and hypothalamic levels ( Table 1 ). Among pituitary hormones, only the secretion of prolactin is increased in the absence of hypothalamic influence, because it is mainly under tonic suppression by dopamine, the main prolactin inhibitory factor. All anterior pituitary hormones are secreted in a pulsatile fashion and tend to follow a diurnal pattern.
10. Table 1: Relationship Among Hypothalamic, Pituitary, and Feedback Hormones and Target Glands ACTH, adrenocorticotropic hormone; ADH, antidiuretic hormone; CRH, corticotropin-releasing hormone; E2, estradiol; GHRH, growth hormone–releasing hormone; IGF-1, interleukin growth factor 1; LHRH, luteinizing hormone–releasing hormone; PIF, prolactin release inhibitory factor; SMS, somatostatin; T, testosterone; T3, triiodothyronine; T4, thyroxine; TRH, thyrotropin-releasing hormone. Antidiuretic hormone (ADH, vasopressin) is produced by the supraoptic and paraventricular nuclei of the hypothalamus and travel in the axons through the pituitary stalk to the posterior pituitary gland. The chief physiologic stimulus of ADH secretion is an increase in serum osmolality and a decrease in plasma volume, resulting in water reabsorption at the level of the distal collecting ducts of the kidneys. Small increments in serum osmolality, more than 290 mOsm/kg, lead to a prompt secretion of ADH.
14. This is an unpaired small ovoid gland and is no longer than the end of the little finger.
15. It is located at the base of the brain and lies below the diencephalon in a depression of basis phenoidboneof the skull called Sella Turcica.
16.
17. The gland is connected to a region of the brain called the hypothalamus by the pituitary stalk. Directly above the pituitary gland and in front of the pituitary stalk are the crossing fibers of the optic nerves, called the optic chiasm.
18. On each side of the pituitary gland is the cavernous sinus. Through each cavernous sinus runs a carotid artery that carries blood to the brain, and important nerves that control eye movements.
19.
20. Parts of Pituitary Gland: Pituitary gland is divided into 3 parts: PITUITARY GLAND Anterior pituitary (Adenohypophysis) Posterior pituitary (Neurohypophysis) Pars Intermedia
21.
22. The anterior pituitary regulates several physiological processes including stress, growth, and reproduction.
23. Its regulatory functions are achieved through the secretion of various peptide hormones that act on target organs including the adrenal gland, liver, bone, thyroid gland, and gonads.
24. The anterior pituitary itself is regulated by the hypothalamus and by negative feedback from these target organs.
25. Disorders of the anterior pituitary are generally classified by the presence of over- or underproduction of pituitary hormones.
26. For example, a prolactinoma is a pituitary adenoma that overproduces prolactin. I
27. n Sheehan's syndrome of postpartum hypopituitarism, the anterior pituitary uniformly malfunctions and underproduces all hormones.
28.
29. Pars tuberalis The pars tuberalis, or "tubular part", forms a sheath extending up from the pars distalis and wrapping around the pituitary stalk. Its function is poorly understood.
30.
31. The secretion of hormones from the posterior pituitary is controlled directly by neurons in the hypothalamus (Marieb, 2004).
32. The connecting stalk between the hypothalamus and the lobes of the pituitary gland, the infundibulum, carries the hormones of the posterior pituitary from nuclei in the hypothalamus.
33. The hypothalmicsupraoptic nuclei manufacture anti-diruetic hormone and the hypothalmicparaventricular nuclei manufacture oxytocin.
34. These hormones are then stored in pituitary axons until their release is triggered (Marieb, 2004).
35. The anterior pituitary is a glandular secretory organ (Wheater, Burkitt & Daniels, 1987).
36. The secretion of hormones from the anterior pituitary is controlled by inhibiting and releasing factors secreted by neurons in the hypothalamus.
37. These inhibiting and releasing factors are release into a primary capillary plexus where they travel, via portal veins, to a secondary capillary plexus where they stimulate the glandular tissue of the anterior pituitary to release its hormones.Embryology: The anterior pituitary arises from an invagination of the oral ectoderm and forms Rathke's pouch. This contrasts with the posterior pituitary, which originates from neuroectoderm.
42. In human fetal life, this area produces melanocyte stimulating hormone or MSH which causes the release of melanin pigment in skin melanocytes (pigment cells).
50. Adrenocorticotropic Hormone (ACTH): Triggers the adrenal glands, which regulate stress response with the release of hormones such as cortisol and aldosterone.
54. it is released in large amounts after distension of the cervix and uterus during labor
55. after stimulation of the nipples, facilitating birth and breastfeedingreastfeeding.
56. Recent studies have begun to investigate oxytocin's role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, and maternal behaviors
57.
58. ThyroidStimulatingHormone(TSH): Thyroid-stimulating hormone (also known as TSH or thyrotropin) is a peptide hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland, which regulates the endocrine function of the thyroid gland Regulation of thyroid hormone levels: TSH stimulates the thyroid gland to secrete the hormones thyroxine (T4) and triiodothyronine (T3).TSH production is controlled by thyrotropin-releasing hormone (TRH), which is manufactured in the hypothalamus and transported to the anterior pituitary gland via the superior hypophyseal artery, where it increases TSH production and release. Somatostatin is also produced by the hypothalamus, and has an opposite effect on the pituitary production of TSH, decreasing or inhibiting its release. The level of thyroid hormones (T3 and T4) in the blood has an effect on the pituitary release of TSH; when the levels of T3 and T4 are low, the production of TSH is increased, and, on the converse, when levels of T3 and T4 are high, TSH production is decreased. This effect creates a regulatory negative feedback loop
59.
60. The TSH receptor The TSH receptor is found mainly on thyroid follicular cells.Stimulation of the receptor increases T3 and T4 production and secretion. Stimulating antibodies to this receptor mimic TSH and cause Graves' disease. Diagnostic: Further information: Reference ranges for blood tests.Thyroid hormones TSH levels are tested in the blood of patients suspected of suffering from excess (hyperthyroidism), or deficiency (hypothyroidism) of thyroid hormone. In general, a standard reference range for TSH for adults is between 0.4 and 5.0 µIU/mL (equivalent to mIU/L), but values vary slightly among labs. The therapeutic target range TSH level for patients on treatment ranges between 0.3 to 3.0 μIU/L.The interpretation depends also on what the blood levels of thyroid hormones (T3 and T4) are. TSH levels for children normally start out much higher. In 2002, the National Academy of Clinical Biochemistry (NACB) in the United States recommended age-related reference limits starting from about 1.3 to 19 µIU/mL for normal-term infants at birth, dropping to 0.6–10 µIU/mL at 10 weeks old, 0.4–7.0 µIU/mL at 14 months and gradually dropping during childhood and puberty to adult levels, 0.4–4.0 µIU/mL. The NACB also stated that it expected the normal (95%) range for adults to be reduced to 0.4–2.5 µIU/mL, because research had shown that adults with an initially measured TSH level of over 2.0 µIU/mL had "an increased odds ratio of developing hypothyroidism over the [following] 20 years, especially if thyroid antibodies were elevated"
61. A TSH assay is now also the recommended screening tool for thyroid disease. Recent advances in increasing the sensitivity of the TSH assay make it a better screening tool than free T4
62. Growth Hormone (GH): Growth hormone (GH) is a protein-based peptide hormone. It stimulates growth, cell reproduction and regeneration in humans and other animals. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior pituitary gland. Somatotropin refers to the growth hormone produced naturally in animals, whereas the term somatropin refers to growth hormone produced by recombinant DNA technology,and is abbreviated "HGH" in humans. Growth hormone is used in medicine to treat children's growth disorders and adult growth hormone deficiency. In recent years, growth hormone replacement therapies have become popular in the battle against ageing and obesity. Reported effects on GH-deficient patients (but not on healthy people) include decreased body fat, increased muscle mass, increased bone density, increased energy levels, improved skin tone and texture, increased sexual function, and improved immune system function. At this time, hGH is still considered a very complex hormone, and many of its functions are still unknown. In its role as an anabolic agent, HGH has been used by competitors in sports since the 1970s, and it has been banned by the IOC and NCAA. Traditional urine analysis could not detect doping with HGH, so the ban was unenforceable until the early 2000s when blood tests that could distinguish between natural and artificial hGH were starting to be developed. Blood tests conducted by WADA at the 2004 Olympic Games in Athens, Greece primarily targeted HGH.
63. Structure: The major isoform of the human growth hormone is a protein of 191 amino acids and a molecular weight of 22,124 daltons. The structure includes four helices necessary for functional interaction with the GH receptor. It appears that, in structure, GH is evolutionarily homologous to prolactin and chorionic somatomammotropin. Despite marked structural similarities between growth hormone from different species, only human and primate growth hormones have significant effects in humans. Several molecular isoforms of GH exist in the pituitary gland and are released to blood. In particular, a ~ 20 kDa variant originated by an alternative splicing is present in a rather constant 1:9 ratio,while recently an additional variant of ~ 23-24 kDa has also been reported in post-exercise states at higher proportions.This variant has not been identified, but it has been suggested to coincide with a 22 kDaglycosilated variant of 23 kDa identified in the pituitary gland.Furthermore, these variants circulate partially bound to a protein (growth hormone-binding protein, GHBP), which is the truncated part of the growth hormone receptor, and an acid-labile subunit (ALS).
64.
65. Effects of growth hormone on the tissues of the body can generally be described as anabolic (building up).
66. Like most other protein hormones, GH acts by interacting with a specific receptor on the surface of cells.
67. Increased height during childhood is the most widely known effect of GH. Height appears to be stimulated by at least two mechanisms
69. Thus, GH exerts some of its effects by binding to receptors on target cells, where it activates the MAPK/ERK pathway.
70.
71. The liver is a major target organ of GH for this process and is the principal site of IGF-1 production. IGF-1 has growth-stimulating effects on a wide variety of tissues.
72.
73.
74. It is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress (along with corticotropin-releasing hormone from the hypothalamus).
75.
76.
77. ACTH acts at several key steps to influence the steroidogenic pathway in the adrenal cortex:
78. ACTH stimulates lipoprotein uptake into cortical cells. This increases the bio-availability of cholesterol in the cells of the adrenal cortex.
79. ACTH increases the transport of cholesterol into the mitochondria and activates its hydrolysis.
80.
81. LH in females: In sexually-mature females, a surge of LH triggers the completion of meiosis I of the egg and its release (ovulation) in the middle of the cycle; stimulates the now-empty follicle to develop into the corpus luteum, which secretes progesterone during the latter half of the menstrual cycle. Women with a severe LH deficiency can now be treated with human LH (Luveris) produced by recombinant DNA technology. LH in males: LH acts on the interstitial cells (also known as Leydig cells) of the testes stimulating them to synthesize and secrete the male sex hormone, testosterone. LH in males is also known as interstitial cell stimulating hormone (ICSH).
82. Normal levels LH levels are normally low during childhood 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.
83.
84. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland.
85. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body.
86. FSH and Luteinizing hormone (LH) act synergistically in reproduction.Structure: FSH is a glycoprotein. Each monomeric unit is a protein molecule with a sugar attached to it; two of these make the full, functional protein. Its structure is similar to those of LH, TSH, and hCG. The protein dimer contains 2 polypeptide units, labeled alpha and beta subunits. The alpha subunits of LH, FSH, TSH, and hCG are identical, and contain 92 amino acids. The beta subunits vary. FSH has a beta subunit of 118 amino acids (FSHB), which confers its specific biologic action and is responsible for interaction with the FSH-receptor. The sugar part of the hormone is composed of fucose, galactose, mannose, galactosamine, glucosamine,andsialic acid, the latter being critical for its biologic half-life. The half-life of FSH is 3–4 hours
87. FSH in females: In sexually-mature females, FSH (assisted by LH) acts on the follicle to stimulate it to release estrogens. FSH produced by recombinant DNA technology (Gonal-f) is available to promote ovulation in women planning to undergo in vitro fertilization (IVF) and other forms of assisted reproductive technology. FSH in males: In sexually-mature males, FSH acts on spermatogonia stimulating (with the aid of testosterone) the production of sperm.
88.
89. Prolactin is a peptide hormone discovered by Dr. Henry Friesen, primarily associated with lactation. In breastfeeding, the act of an infan suckling the nipple stimulates the production of oxytocin which stimulates the "milk let-down" reflex,which fills the breast with milk via a process called lactogenesis, in preparation for the next feed.
90. Pituitary prolactin secretion is regulated by neuroendocrine neurons in the hypothalamus, the most important ones being the neurosecretorytuberoinfundibulum (TIDA) neurons of the arcuate nucleus, which secrete dopamine to act on the dopamine-2 receptors of lactotrophs, causing inhibition of prolactin secretion. Thyrotropin releasing factor (thyrotropin-releasing hormone) has a stimulatory effect on prolactin release.
91.
92.
93. They were first isolated by the Yale professor Aaron B. Lerner.
94. Synthetic analogs of these naturally occurring hormones have also been developed and researched.Function: They stimulate the production and release of melanin (melanogenesis) by melanocytes in skin and hair. MSH signals to the brain have effects on appetite and sexual arousal. Structure of MSH: Melanocyte-stimulating hormone belongs to a group called the melanocortins. This group includes ACTH, alpha-MSH, beta-MSH and gamma-MSH; these peptides are all cleavage products of a large precursor peptide called pro-opiomelanocortin (POMC). Alpha-MSH is the most important melanocortin for pigmentation. The different melanocyte-stimulating hormones have the following amino acid sequences:
96. Oxytocin: Oxytocin (pronounced /ˌɒksɨˈtoʊsɪn/) is a mammalian hormone that acts primarily as a neurotransmitter in the brain. Also known as alpha-hypophamine (α–hypophamine), oxytocin has the distinction of being the very first polypeptide hormone to be sequenced and synthesized biochemically by Vincent du Vigneaud et al. in 1953. Oxytocin is best known for its roles in female reproduction: 1) it is released in large amounts after distension of the cervix and uterus during labor, and 2) after stimulation of the nipples, facilitating birth and breastfeeding. Recent studies have begun to investigate oxytocin's role in various behaviors, including orgasm, social recognition, pair bonding, anxiety, and maternal behaviors.For this reason, it is sometimes referred to as the "love hormone."
102. The inactive precursor protein is progressively hydrolyzed into smaller fragments (one of which is neurophysin I) via a series of enzymes.
103. The last hydrolysis which releases the active oxytocinnonapeptide is catalyzed by peptidylglycine alpha-amidatingmonooxygenase (PAM).
104. The activity of the PAM enzyme system is dependent upon ascorbate which is a necessary vitamin cofactor. By chance, it was discovered that sodium ascorbate by itself stimulated the production of oxytocin from ovarian tissue over a range of concentrations in a dose-dependent manner.
105.
106. Non-neural sources Outside the brain, oxytocin-containing cells have been identified in several diverse tissues including the corpus luteum.the interstitial cells of Leydig,theretina,the adrenal medulla,theplacenta,thethymusand the pancreas.The finding of significant amounts of this classically "neurohypophysial" hormone outside the central nervous system raises many questions regarding its possible importance in these different tissues. Female Oxytocin is synthesized by corpora lutea of several species, including ruminants and primates. Along with estrogen, it is involved in inducing the endometrial synthesis of prostaglandin F2α to cause regression of the corpus luteum. Male The Leydig cells in some species have also been shown to possess the biosynthetic machinery to manufacture testicular oxytocinde novo, specifically, in rats (who can synthesize Vitamin C endogenously), and in guinea pigs who (like humans) require an exogenous source of vitamin C (ascorbate) in their diets.
107.
108. The sequence is cys– tyr– ile – gln – asn – cys – pro – leu – gly- NH2 (CYIQNCPLG-NH2).
109. The cysteine residues form a sulfur bridge. Oxytocin has a molecular mass of 1007 daltons.
110. One international unit (IU) of oxytocin is the equivalent of about 2 micrograms of pure peptide.
111. The biologically active form of oxytocin, commonly measured by RIA and/or HPLC techniques, is also known as the octapeptide "oxytocin disulfide" (oxidized form), but oxytocin also exists as a reduced dithiolnonapeptide called oxytoceine.
112.
113. Industrial use of drug: Oxytocin can be administered to bovine animals in order to increase the production of dairy milk. Misuse of drug: Reports exist of hundreds of girls being kidnapped from across India and brought to Sodhawas and Geerwar villages in Alwar district of Rajasthan, where they are given oxytocin injections to hasten their puberty and pushed into prostitution. The kidnapped girls have reportedly been as young as six-month-old babies. They are raised by the villagers as their own daughters
121. give little or no help with the care of their young.Meadow voles whose brains have been injected with a vector causing increased expression of the V1a receptor become more like prairie voles in their behavior. (See Lim, M. M. et al., Nature, 17 June 2004.) The level of expression of the V1a receptor gene is controlled by a "microsatellite" region upstream (5') of the ORF. This region contains from 178 to 190 copies of a repeated tetranucleotide (e.g., CAGA). Prairie voles have more copies of the repeat than meadow voles, and they express higher levels of the receptor in the parts of the brain associated with these behaviors. A similar microsatellite region is present in the pygmy chimpanzee or bonobo (Pan paniscus) but is much shorter in the less-affectionate common chimpanzee (Pan troglodytes). Changes in the regulatory region of the human gene for the V1a receptor have been linked to autism.
122.
123. Secretion in response to reduced plasma volume is activated by pressure receptors in the veins. atria, and carotids.
124. Secretion in response to increases in plasma osmotic pressure is mediated by osmoreceptors in the hypothalamus.
125. Secretion in response to increases in plasma cholecystokininis mediated by an unknown pathway.
126. The neurons that make AVP, in the hypothalamic supraoptic nuclei (SON) and paraventricular nuclei (PVN), are themselves osmoreceptors, but they also receive synaptic input from other osmoreceptors located in regions adjacent to the anterior wall of the third ventricle. These regions include the organumvasculosum of the lamina terminalis and the subfornical organ.
128. Ethanol(alcohol) acts as an antagonist for AVP in the collecting ducts of the kidneys, which prevents aquaporins from binding to the collecting ducts, and prevents water reabsorption.
129.
130. The AVP that is measured in peripheral blood is almost all derived from secretion from the posterior pituitary gland (except in cases of AVP-secreting tumours). However there are two other sources of AVP with important local effects:
131. Vasopressin is produced in the PVN and SON and travels down the axons through the infundibulum within neurosecretory granules that are found within Herring bodies, localized swellings of the axons and nerve terminals. These carry the peptide directly to the posterior pituitary gland, where it is stored until released into the blood.
132. Vasopressin is also released into the brain by several different populations of smaller neuronsReceptors Below is a table summarizing some of the actions of AVP at its three receptors, differently expressed in different tissues and exerting different actions:
133.
134. Structure and relation to oxytocin: Chemical structure of argipressin The vasopressins are peptides consisting of nine amino acids (nonapeptides). (NB: the value in the table above of 164 amino acids is that obtained before the hormone is activated by cleavage). The amino acid sequence of arginine vasopressin is Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly, with the cysteine residues forming a sulfur bridge. Lysine vasopressin has a lysine in place of the arginine. The structure of oxytocin is very similar to that of the vasopressins: It is also a nonapeptide with a disulfide bridge and its amino acid sequence differs at only two positions (see table below). The two genes are located on the same chromosome separated by a relatively small distance of less than 15,000 bases in most species. The magnocellular neurons that make vasopressin are adjacent to magnocellular neurons that make oxytocin, and are similar in many respects. The similarity of the two peptides can cause some cross-reactions: oxytocin has a slight antidiuretic function, and high levels of AVP can cause uterine contractions. Here is a table showing the superfamily of vasopressin and oxytocinneuropeptides:
135.
136.
137.
138. While most are benign, they can produce excessive amounts of a specific pituitary
139. hormone, crowd out the production of other hormones, and compress surrounding tissues.
140. Blood vessels and the optic nerves are in close proximity to the pituitary gland. Pressure from a tumor can cause headaches, visual disturbances, loss of vision, fatigue, weakness, and seizures, as well as a host of signs and symptoms related to diminished hormone production.
141. Other pituitary disorders can arise from inherited genetic mutations, be congenital, be due to trauma or an impaired blood supply, due to surgical or radiation treatment of a previous pituitary disorder, due to a malignant tumor (rare), or be due to causes that are not yet well understood.
142. The hormone deficiencies and excesses from these disorders can produce a variety of symptoms depending on which hormones and target tissues are affected.
143. When the hypothalamus is dysfunctional, pituitary hormone production is often affected.
154. Signs and symptoms: Pituitary tumors may manifest with signs and symptoms related to pituitary hypofunction, specific hormone(s) hypersecretion, and/or mass effect. Impingement on the chiasm or its branches by a pituitary tumor may result in visual field defects; the most common is bitemporalhemianopsia Lateral extension of the pituitary mass to the cavernous sinuses may result in diplopia, ptosis, or altered facial sensation.Among the cranial nerves, the third nerve is the most commonly affected. There is no specific headache pattern associated with pituitary tumors and, in some patients, the headache is unrelated to pituitary adenoma.
155.
156. Treatment: With exogenous GH is indicated only in limited circumstances and needs regular monitoring due to the frequency and severity of side-effects
157. Hypopituitarism: from a variety of causes including tumors, trauma, decreased pituitary blood supply, infection, sarcoidosis, an autoimmune process, radiation, surgical removal of the pituitary, or a side effect of pituitary surgery; results in a general decrease in pituitary hormone production.
158. Treatment: Treatment of hypopituitarism is threefold: removing the underlying cause, treating the hormone deficiencies, and addressing any other repercussions that arise from the hormone deficiencies
164. symptoms vary but include: upper body obesity, a rounded face, thin skin, pink streaks on the abdomen, muscular weakness, osteoporosis, high blood sugar, and high blood pressure
165. Treatment :depends on whether the problem is in the adrenal glands, the pituitary gland, or elsewhere. Surgery or radiation therapy may be needed to remove or destroy a pituitary tumor. Tumors of the adrenal gland (usually adenomas) can often be removed surgically. Both adrenal glands may have to be removed if these treatments are not effective or if no tumor is present.Diabetes Incipidus:Central diabetes insipidus is a lack of antidiuretic hormone that causes excessive production of very dilute urine (polyuria). Central diabetes insipidus has several causes, including a brain tumor, tuberculosis, a brain injury or surgery, and some forms of other diseases. The main symptoms are excessive thirst and excessive urine production. The diagnosis is based on urine tests, blood tests, and a water deprivation test. People with central diabetes insipidus usually are given the drugs vasopressin or desmopressin as a nasal spray.
166.
167. Nelson’s Syndrome: may result when both adrenal glands are removed as part of the treatment for Cushing’s Disease; a pituitary tumor develops that produces ACTH .
168. Symptoms: cause darkening of the skin due to increased production of melanocyte stimulating hormone (MSH) disturbances, and delayed growth.
