Hormones and Disorders of the Pituitary Gland (Exam 2)

A hormone is a chemical substance produced in the body that has a specific ______ effect on the activity of a certain organ or cell within that organ.

regulatory

What are some functions of hormones?

- Body homeostasis (regulation of glucose and water balance)

- Growth and development

- Sexual maturation, rhythms and reproduction

- Regulate energy production and use

- Control stress response and fight/flight response

- Control release of other hormones

What are the major endocrine glands of the body?

- Hypothalamus

- Pituitary gland

- Parathyroid glands

- Thyroid gland

- Adrenal glands

- Pancreas

- Ovaries (females), testes (males)

What hormones is the anterior pituitary gland responsible for?

- TSH

- ACTH

- LH

- FSH

- GH

- Prolactin

What hormones are stored in the posterior pituitary gland?

- Oxytocin

- Vasopressin (aka ADH)

The two subunits of hormones are ______ and ______.

alpha, beta

The beta subunit provides ______.

specificity

The alpha subunit is ______ while the beta subunit is ______.

common, unique

Subunits for LH, TSH, FSH, and hCG

⍺ + βLH = LH

⍺ + βTSH = TSH

⍺ + βFSH = FSH

⍺ + βhCG = hCG

Antidiuretic hormone/ADH is the hormone ______.

vasopressin

Oxytocin is essential in ______ and ______.

childbirth, milk let-down

Neurons that stimulate hypothalamic releasing/inhibiting hormones are influenced by ______.

neurotransmitters (dopamine, norepinephrine, serotonin, acetylcholine, endorphins)

Feedback control between the pituitary gland and target organs operates in a ______ feedback way.

negative

Growth Hormone (GH) is produced by the ______ pituitary gland.

anterior

GH is stimulated by ______.

GH-RH

GH is inhibited by ______.

somatostatin

GH exhibits ______ secretion throughout the day.

pulsatile

GH promotes growth of ...

- Soft tissue

- Cartilage

- Bone

GH stimulates release of ______ by the liver.

insulin-like growth factor (IGF)

GH inhibits the action of ______.

insulin

GH increases blood ______.

glucose

Both GH and IGF are measured via ______.

immunoassay

GH excess in adults is called ______.

acromegaly

GH excess in children is called ______.

gigantism

How is GH excess (acromegaly) tested for in the lab?

The patient's baseline GH is measured, they are given a 100g glucose load, then GH is measured again.

After a glucose suppression test for acromegaly, GH should be ______ in healthy people.

suppressed

In patients with acromegaly, GH will remain ______ after a glucose suppression test

elevated

GH deficiency in children is known as ______.

pituitary dwarfism

How can a child get a GH deficiency?

- Inherited

- Anatomical changes in the pituitary gland or hypothalamus

- Deficiency in other pituitary hormones

GH deficiency in children is treated with ______.

recombinant GH

GH deficiency can be tested via ______ in children.

exercise/deep sleep

Adults can be given ______ to induce hypoglycemia to test GH deficiency.

insulin

If a child or adult has a GH deficiency, their GH levels will remain ______ after testing (exercise/deep sleep or insulin).

low

IGF levels are low with GH deficiency, but ______.

non-specific

Prolactin (PRL) stimulates and sustains post-partum ______.

lactation

PRL secretion is inhibited by ______.

dopamine

______ is the most common hypothalamic-pituitary disorder in both sexes.

Hyperprolactinemia

______ are the most common secretory tumors of the pituitary gland.

Prolactinomas

What S/Sx do men experience when they have hyperprolactinemia?

Oligospermia, impotence, visual issues

What S/Sx do women experience when they have hyperprolactinemia?

PCOS, infertility

______ is most commonly used in the lab to analyze PRL.

Immunoassay

PRL is susceptible to the ______.

hook effect

Macroprolactin is generally not harmful to a patient, but can be a source of false ______.

positives

Antidiuretic Hormone (ADH) is synthesized in the hypothalamus as part of the ______ precursor molecule.

preprovasopressin

ADH is stored in the ______.

posterior pituitary lobe

What are the functions of ADH?

- Water reabsorption in renal tubules

- Stimulate contraction of muscles/capillaries

- Increase peristalsis

Hypofunction of ADH can cause ______.

diabetes insipidus

Hyperfunction of ADH can cause ______.

SIADH

When a patient has diabetes insipidus due to deficient production/action of ADH, it results in ______ and ______.

polyuria, polydipsia

What are the lab indications of diabetes insipidus due to ADH deficiency?

Dehydration/hypernatremia with elevated serum osmolality and decreased urine osmolality

What are the three main states of diabetes insipidus?

1. Hypothalamic

2. Nephrogenic

3. Dispogenic

Hypothalamic diabetes insipidus (HDI) is caused by the failure of the pituitary gland to secrete ______ in response to regulatory factors.

(regular amounts of) ADH

HDI can be diagnosed through a ______ test.

water deprivation

Steps of a water deprivation test

1. Patient is deprived of all fluids until urine osmolality is consistent

2. Base ADH is measured

3. ADH is given, urine and serum osmolality are analyzed

Nephrogenic diabetes insipidus (NDI) is caused by failure of the kidneys to ______ typical or increased concentrations of ADH.

respond to

Oxytocin is synthesized in the ______ as part of preprovasopressin.

hypothalamus

Oxytocin is stored in the ______.

posterior pituitary

Oxytocin promotes ______ and ______.

labor, milk release

Oxytocin can be measured (rare) via ______, and is also being looked at as an anti-stress hormone.

immmunoassay

Assessment of the hypothalamic-pituitary-end organ axis starts with baseline ______ levels.

hormone

Pituitary: ACTH, TSH, LF, FSH

End organ: Cortisol, thyroxine, testosterone, etc.

If hypofunction is suspected, ______ are performed.

stimulation

If hyperfunction is suspected, ______ tests are performed.

suppression

(patient given a hormone that will suppress secretion)