Endocrinology and Pituitary Hormones

Flashcards covering the fundamentals of Endocrinology, hypothalamic-pituitary axes, hormone functions, and clinical assessments/disorders of the pituitary gland.

Endocrinology

The study of endocrine glands and the hormones they produce.

Hormones

Substances (either protein or carbohydrate) released into circulation that travel to a target organ to produce a certain reaction or act as a stimuli.

Thyrotropin-Releasing Hormone (TRH)

A hormone produced by the hypothalamus to stimulate the anterior pituitary gland to release thyroid stimulating hormone (TSH).

Corticotropin Releasing Hormone (CRH)

A hypothalamic hormone that stimulates the anterior pituitary to produce Corticotropin or Adrenocorticotropic Hormone (ACTH).

Gonadotropin-releasing hormone (GnRH)

A hormone produced by the hypothalamus to stimulate the anterior pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

Growth Hormone – Inhibiting Hormone (GHIH)

Also known as Somatostatin, this hypothalamic hormone functions to inhibit the release of growth hormone (GH).

Sella Turcica

A location on the basal floor of the skull where the pituitary gland is located.

Somatomammotropic (Lactogenic) Family

A family of anterior pituitary hormones that includes Growth Hormone (GH) and Prolactin (PRL).

Glycoproteins (Pituitary Family)

A family of anterior pituitary hormones sharing a common a subunit, including TSH, FSH, and LH.

Proopiomelanocortin (POMC)

A family of anterior pituitary hormones that includes ACTH and MSH.

Tropic Hormones

Hormones that stimulate the secretion of other hormones from target glands; examples include TSH, ACTH, FSH, and LH.

Somatotropin

Another name for Growth Hormone (GH), the primary hormone responsible for regulating overall body growth and intermediary metabolism.

Amphibolic Hormone

A term describing the function of Growth Hormone (GH) in propagated body cell growth (’pampalaki ng katawan’).

Oral Glucose Suppression Test

A test to assess GH secretion where $100\,gm$ of glucose is loaded after a $12\,hr$ fast; normally GH levels decrease or become undetected.

Gigantism

A condition caused by a GH producing tumor occurring before the epiphyseal plate closing.

Acromegaly

A condition due to pathologic or autonomous excess of Growth Hormone after epiphyseal plate closing, often associated with a pituitary tumor.

GHRH deficiency

The most common genetic cause of Growth Hormone deficiency where the hypothalamus cannot signal the pituitary to synthesize GH.

Dopamine

Also known as Prolactin Inhibitory Factor, it is the major regulator that inhibits the release of Prolactin.

Hypogonadism

The inhibition of gonadal function (testes and ovary) that occurs as an effect of the overproduction of Prolactin.

Macroprolactinoma

A functional pituitary tumor characterized by the production of a $150\,kD$ Prolactin molecule.

Panhypopituitarism

The complete loss of function of the pituitary gland.

Positive Feedback Loop

The mechanism of Oxytocin secretion where increasing concentrations trigger the posterior pituitary to release even more hormone for stronger contractions.

Vasopressin (ADH)

A cyclic nonapeptide that conserves water during urine formation and promotes clotting by releasing Factor VII and Von Willebrand Factor (VWF).

Diabetes Insipidus

A condition caused by Vasopressin deficiency, characterized by polydipsia (excessive thirst) and polyuria (excessive urination).

Water Deprivation Test

A diagnostic test for Vasopressin deficiency where elevated plasma osmolality and decreased urine osmolality under deprivation signify a deficiency.

Desmopressin Test

A diagnostic method for Vasopressin deficiency where the administration of a Vasopressin analog leads to the diminishment of polyuria and polydipsia.