Endocrine System Review

• The pituitary gland is located next to the hypothalmus in the brain
• The pituitary gland has two lobes, the anterior and posterior lobes
• The pituitary gland releases hormones

Anterior Pituitary Hormones

• The anterior pituitary is also known as the adenohypophysis
• Growth hormone (GH) target bones and tissues to promote growth through lipolysis, CHON anabolism, and insulin antagonism.
  • Hypersecretion of GH in children causes Gigantism
  • Hypersecretion of GH in adults causes Acromegaly
  • Hyposecretion of GH in young people causes Dwarfism
  • Hyposecretion of GH in adults causes Cachexia
• Prolactin (PRL), also known as Mammotropic, Lactotropic, Luteotropic Hormone, targets the Breast & Gonads, and stimulates lactation and mammary tissue growth
  • Necessary for breast development and lactation & Regulator of reproduction in males and females and Maintains the corpus luteum & progesterone secretion
  • Hypersecretion of PRL leads to Galactorrhea
  • Hyposecretion of PRL leads to Absence of milk during lactation
• Thyroid-stimulating hormone (TSH) has the thyroid gland as its target.
  • Necessary for growth & functions of thyroid and control for all thyroid functions
  • TSH Stimulates secretions & release of T3, T4, & Thyrocalcitonin
  • Hypersecretion of TSH causes Secondary Hypothyroidism
  • Hyposecretion of TSH causes Secondary Hyperthyroidism
• Adrenocorticotropic hormone (ACTH) is the primary hormone that targets the adrenal cortex to release of its hormones and cause adrenocorticol growth.
  • Necessary for growth & size of cortex
  • Plays a minor role in the release of mineralocorticoids
  • Hypersecretion of ACTH causes Secondary Cushing Disorder
  • Hyposecretion of ACTH causes Secondary Addison's Disease
• Gonadotropins target the ovaries and testes to stimulate gametogenesis and sex steroid production
  • Follicle-stimulating hormone (FSH) stimulates follicle development & the secretion of estrogen. In testes, Germinal Stimulating Hormone stimulates sperm production
  • Luteinizing hormone (LH) is responsible for ovulation, corpus luteum development and progesterone secretion. In testes, Interstitial Cell Stimulating Hormone stimulates cell-producing testosterone
  • Hypersecretion of Gonadotropins will cause Precocious puberty–Early puberty
  • Hyposecretion of Gonadotropins in males can cause small phallus & testicles, no body hair growth, decrease libido, impotence and aspermia
  • Hyposecretion of Gonadotropins in females can cause failure to develop breast, no body hair growth, no ovulation, no menstruation and infertility

Posterior Pituitary Hormones

• The posterior pituitary gland is also known as the neurohypophysis
• Antidiuretic hormone (ADH) goes to the kidney and promotes water reabsorption; ADH is also known as VASOPRESSIN
  • Hypersecretion of ADH results in Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
  • Hyposecretion of ADH results in Diabetes insipidus
• Oxytocin goes to the breast and uterus, stimulates uterine contraction & breast milk ejection, stimulates prolactin release and fallopian tube contraction facilitating migration of sperm

Disorders of the Pituitary Gland

• It is important to generally assess for Hemianopsia or headache, weight loss and/or emaciation, hair loss, impotence, amenorrhea or adrenal insufficiency
• Skull X-rays, CT scans and MRIs can be used as diagnostic tests of the pituitary gland

Hypopituitarism

• Results from a deficiency of one or more pituitary hormones
• It may occur because of disease in the hypothalamic center, or from problems directly involving the pituitary glands.
• May be be caused by a tumor, trauma, surgical removal, irradiation or congenital deficiency
• General signs of hypopituitarism include hemianopsia, headache, weight loss, emaciation, hair loss, impotence, amenorrhea and/or adrenal insufficiency
• Medical intervention involves surgical removal of a tumor and hormone replacement therapy (HRT)
• A Hypophysectomy, the surgical removal of the pituitary gland entails a transsphenoidal approach
• Post operative nursing interventions for a transsphenoidal hypophysectomy include elevating the head of the bed; reinforcing the nasal packing; providing oral care; preventing increases to the ICP; assessin for CSF leaks administering corticosteroids

Diseases of Hypopituitarism

• Dwarfism is stunted growth, can be treated with Somatrem/Protropin and Somatropin/Humatrope
• Cachexia is a state of poor health and malnutrition
  • Other symptoms include emaciation, atrophy of genitals and loss of secondary sex characteristics
  • May be atrophy of Pituitary Gland
  • Treated Symptomatically
• Hypogonadism involves changes in secondary sex characteristics
  • Women may experience amenorrhea, breast atrophy and infertility
  • Men may experience small testes & phallus, decrease libido, aspermia and impotence
  • Treatment includes replacement of missing hormones, Clomid (F) and Androgen (M)

Hyperpituitarism

• Hyperpituitarism involves hyperfunction of the anterior pituitary resulting in oversecretion of one or more of the anterior pituitary hormones
• Causes may include a benign pituitary adenoma, hyperplasia of pituitary tumors or prolactinomas secreting tumors.
• Assessment includes neurological examination, looking for hemianopsia, blindness, visual disturbances, headache, somnolence or signs of increased ICP or hypothalamic involvement
  • Endocrine changes include irregular menses, anovulatory periods, infertility and galactorrhea in females and reduced sperm count or gynecomastia in males
• Medical management includes surgery, radiation and pharmacotherapy like Sandostatin or Bromocriptine Mesylate
• Nursing interventions include monitoring for hyperglycemia and cardiovascular complications and preparation for hypophysectomy or radiation therapy
• Postoperative interventions include elevating the bed, reinforcing the nasal packing and avoiding activities that raise ICP

Diseases of Hyperpituitarism

• Acromegaly occurs in adults and affects the bones after the epiphyseal closure.
  • The bone grow wider and thicker, commonly affecting the jaw and extremities
• Gigantism occurs in children with subsequent overgrowth of skeleton and soft tissue.
• Excessive growth of the long bones accompanied by muscular weakness

Posterior Lobe disorders

• Diabetes insipidus is characterized by a deficiency in antidiuretic hormone (ADH)
• Head trauma, brain tumor, surgical removal of PG, CNS infection or failure of renal tubules to respond to ADH can all be causes of an ADH deficiency
• 3 classical signs includes polyuria of 5-20L a day of urine, polydipsia of 2-20L a day of fluid and very dilute urine,
• Fluid deprivation test can be used to assist the diagnosis
• Treatment goals include replacing ADH, and appropriate hydration and correcting the underlying cause by administrating Vasopressin, Clofibrate and Chlorpropamide
• Syndrome of Inappropriate Antidiuretic Hormone (SIADH) is a condition in which there is a continued release of ADH
  • May be caused by trauma, tumors, bronchogenic cancer, CNS disorder or as a response to certain medications
  • Clinical manifestations include low urine output with weight gain or edema, water intoxication, muscular cramps, hyponatremia or seizures
  • Treatment included eliminating cause, limiting fluid intake, using normal saline or administering potassium supplements. Demeclocycline can also be administered to induced water reabsorption by inhibiting ADH and and produce diuresis

Test your knowledge of hormones and their functions. Questions cover growth hormone, prolactin, TSH, Addison's disease, galactorrhea, diabetes insipidus, and SIADH. Identify hormonal imbalances, target organs, and associated conditions.