Growth hormone, Oxytocin, ADH Flashcards
Another name for growth hormone is _
Another name for growth hormone is somatotropin
Growth hormone is a _ type hormone that plays a role in the regulation of bone growth
Growth hormone is a peptide hormone that plays a role in the regulation of bone growth
* It is hydrophilic and can freely travel in the serum
GH is produced by _ cells in the _ pituitary
GH is produced by somatotrophs in the anterior pituitary
The GH receptors on hepatocytes are linked to _ which phosphorylate the _ transcription factors; these TFs are then transported into the nucleus to induce gene transcription to make IGF-1
The GH receptors on hepatocytes are linked to JAKs which phosphorylate the STAT transcription factors; these TFs are then transported into the nucleus to induce gene transcription to make IGF-1
When concerned about a lack of growth we generally measure _ hormone
When concerned about a lack of growth we generally measure IGF-1
* IGF-1 is more stable than GH, which is released in a pulsatile manner
The epiphyseal plate is a plate of _ that is located at the end of a growing long bone
The epiphyseal plate is a plate of hyaline cartilage that is located at the end of a growing long bone
* This is where new growth takes place
By age _ (males) and _ (females) the epiphyseal plate closes
By age 20 (males) and 18 (females) the epiphyseal plate closes
GH and IGF-1 stimulate skeletal muscle growth by _ and _
GH and IGF-1 stimulate skeletal muscle growth by stimulating myocyte hypertrophy and increasing protein synthesis
GH and IGF-1 (increase/decrease) the serum glucose concentration
GH and IGF-1 increase the serum glucose concentration
* Increase hepatic gluconeogenesis
* Increase lipolysis
* Antagonize insulin
Two hormones secreted from the hypothalamus to regulate GH are _ and _
Two hormones secreted from the hypothalamus to regulate GH are GH-releasing hormone (GHRH) and GH-inhibiting hormone (GHIH)
Aging, obesity, and glucose will _ GHRH
Aging, obesity, and glucose will inhibit GHRH
Sleep, hypoglycemia, and stress will _ GHRH
Sleep, hypoglycemia, and stress will stimulate GHRH
Somatostatin will _ GH release from the anterior pituitary
Somatostatin will inhibit GH release from the anterior pituitary
During periods of starvation, fasting, and weight loss, GH is secreted to maintain blood sugar; this is triggered by the gastric hormone _
During periods of starvation, fasting, and weight loss, GH is secreted to maintain blood sugar; this is triggered by the gastric hormone ghrelin
Signs of acquired GH deficiency in adults may involve:
Signs of acquired GH deficiency in adults may involve:
* Decreased muscle mass
* Increased fat mass
* Decreased BMD
* Increased rate of fractures
_ syndrome is an autosomal recessive disorder that involves a mutation in the GH receptor; children present with growth failure, small head circumference, prominent foreheads, saddle nose, small genitalia
Laron syndrome is an autosomal recessive disorder that involves a mutation in the GH receptor; children present with growth failure, small head circumference, prominent foreheads, saddle nose, small genitalia
* They may also have hyperlipidemia, hypoglycemia
_ is an inherited deletion on chromosome 15 that causes childhood obesity and impaired growth
Prader-Willi syndrome is an inherited deletion on chromosome 15 that causes childhood obesity and impaired growth
In a true GH deficiency we expect IGF-1 to be _ and bone age to be _
In a true GH deficiency we expect IGF-1 to be low and bone age to be lower than expected
We can test for GH deficiency with a GH stimulation test; we adminster _ or IV _ to attempt to stimulate GH production
We can test for GH deficiency with a GH stimulation test; we adminster insulin or IV arginine to attempt to stimulate GH production
* Insulin decreases glucose levels –> should increase GH
Excess GH in childhood causes a condition called _
Excess GH in childhood causes a condition called gigantism
* Results in tall children
Excess GH in adulthood causes a condition known as _
Excess GH in adulthood causes a condition known as acromegaly
* This refers to GH excess that occurs after the fusion of the epiphyseal growth plates
Clinical features of acromegaly:
Clinical features of acromegaly:
* Enlarged hands and feet
* Enlarged head circumference
* Enlarged vocal cords (hoarse voice)
* Snoring from airway obstruction
* Joint pain, muscle fatigue
* Coarse facial features
* Enlarged jaw (widely spaced teeth)
GH excess can result in constant elevation of blood glucose levels and can lead to _ and _
GH excess can result in constant elevation of blood glucose levels and can lead to secondary diabetes mellitus and accelerated atherosclerosis
Complications of agromegaly:
Complications of agromegaly:
* Diabetes
* Atherosclerosis
* Hypertension
* Sleep apnea
* Hypogonadism
* Carpal tunnel
* Colon cancer
What is a GH suppression test?
GH suppression test can be given when IGF-1 is elevated and GH excess is suspected; we administer glucose which normally inhibits GH
_ is a somatostatin analog that can be used to decrease GH release
Octreotide is a somatostatin analog that can be used to decrease GH release
* Oct-treo-tide
_ is a GH receptor antagonist that can be used to treat excess GH
Pegvisomant is a GH receptor antagonist that can be used to treat excess GH
* Peg-viso-mant
_ is a dopamine analog which can be used to suppress GH release (second-line option)
Cabergoline is a dopamine analog which can be used to suppress GH release (second-line option)
* Caber-goline
Oxytocin is a _ type hormone
Oxytocin is a neuropeptide hormone
* It is water soluble and travels freely in the bloodstream
Oxytocin is mostly made in the _ of the hypothalamus
Oxytocin is mostly made in the paraventricular nucleus of the hypothalamus
* Made in smaller amounts in the peripheral tissues like the ovaries, placenta, pancreas, etc
Oxytocin is synthesized as an inactive precursor protein which must be cleaved by enzymes; _ is one of these enzymes that is dependent on _
Oxytocin is synthesized as an inactive precursor protein which must be cleaved by enzymes; PAM is one of these enzymes that is dependent on vitamin C
Oxytocin secretion is stimulated by _ trigger from the hypothalamus
Oxytocin secretion is stimulated by an action potential delivered from the hypothalamus
Oxytocin binds its receptor (in the breast and brain) –> activates _ –> initates a signaling cascade and altered gene expression
Oxytocin binds its receptor (in the breast and brain) –> activates MAP kinase –> initates a signaling cascade and altered gene expression
Oxytocin promotes _ of smooth muscle during childbirth
Oxytocin promotes contraction of smooth muscle during childbirth
* Pushes fetus towards the cervix
Rising levels of _ during the third trimester of pregnancy increases oxytocin receptor expression in the uterus
Rising levels of estradiol during the third trimester of pregnancy increases oxytocin receptor expression in the uterus
Cervical dilation during labor activates _ which stimulates (positive/negative) feedback
Cervical dilation during labor activates stretch receptors which stimulates positive feedforward signaling to increase oxytocin
* Oxytocin release even continues after baby is born to reduce bleeding and return uterus to normal size
Pitocin is a synthetic form of _ that is given to initate labor and cause stronger contractions during delivery
Pitocin is a synthetic form of oxytocin that is given to initate labor and cause stronger contractions during delivery
Milk _ is caused by prolactin while milk _ is caused by oxytocin
Milk production is caused by prolactin while milk letdown is caused by oxytocin
Oxytocin (increases/decreases) CRH
Oxytocin decreases CRH release from the hypothalamus
* This decreases ACTH, decreases cortisol release, reduces stress
The main stimuli for oxytocin release are _ and _ (both positive feedback mechanisms)
The main stimuli for oxytocin release are suckling by the infant and dilation of the uterine cervix (both positive feedback mechanisms)
Vasopressin is produced in the hypothalamus by _ and _ nuclei
Vasopressin is produced in the hypothalamus by paraventricular and supraoptic nuclei
Vasopressin’s principal functions are _ and _
Vasopressin’s principal functions are vasoconstriction of arterial smooth muscle and increasing water absorption in the kidney
Vasopressin binds to _ receptors in the vasculature, liver, and brain to stimulate smooth muscle contraction
Vasopressin binds to V1A receptors in the vasculature, liver, and brain to stimulate smooth muscle contraction
ADH binds to _ receptors in the principal cells of the collecting ducts to increase water reabsorption
ADH binds to V2A receptors in the principal cells of the collecting ducts to increase water reabsorption
* Increases the number of aquaporins
ADH binding to the V1B receptors on the anterior pituitary gland causes _
ADH binding to the V1B receptors on the anterior pituitary gland causes ACTH release –> cortisol synthesis
* Cortisol will also support the blood pressure
ADH binding V1A receptors will cause the release of _
ADH binding V1A receptors will cause the release of von Willebrand factor
* This stimulates platelet aggregation and blood clotting
Release of ADH is stimulated by _ or _
Release of ADH is stimulated by increased serum osmolality or extracellular volume
* Increased osmolality is sensed by osmoreceptors in the hypothalamus
* Decreased effective circulating volume is sensed by baroreceptors in heart, vessels, lungs, liver, brain
(True/False) Ang II also stimulates ADH release
True; Ang II also stimulates ADH release
The two main hormones that inhibit ADH effects are _ and _
The two main hormones that inhibit ADH effects are cortisol and ANP
* Cortisol blocks ADH release; ANP blocks ADH effect on the collecting duct
Acromegaly will cause (increased linear bone growth/ disproportionate growth)
Acromegaly will cause disproportionate growth
* Recall that acromegaly occurs after the fusion of epiphyseal plates
* Involves frontal bossing, jaw enlargement, large hands and feet
The most common cause of death in patients with gigantism is _
The most common cause of death in patients with gigantism is heart failure
Acromegaly is associated with _ syndrome due to the compression of the median nerve
Acromegaly is associated with carpal tunnel syndrome due to the compression of the median nerve
Acquired GH deficiency may occur secondary to:
Acquired GH deficiency may occur secondary to:
* Brain tumor
* Surgery
* TBI
* Radiation to pituitary
GH deficiency is associated with a short stature with (proportional/disporportional) measurements
GH deficiency is associated with a short stature with proportional measurements
The most potent regulator of ADH secretion is _
The most potent regulator of ADH secretion is serum osmolality
* Other regulators include blood volume, blood pressure, angiotensin II, cortisol, ANP
(High/Low) cortisol levels stimulate ADH release
Low cortisol stimulates ADH release
Two regulators of oxytocin release are _ and _
Two regulators of oxytocin release are suckling at the breast and uterine stretching
A patient with central DI will have:
_ serum sodium
_ serum osmolality
_ urine osmolality
A patient with central DI will have:
High serum sodium
High serum osmolality
Low urine osmolality
A patient with SIADH will have:
_ serum sodium
_ serum osmolality
_ urine osmolality
A patient with SIADH will have:
Low serum sodium
Low serum osmolality
High urine osmolality
SIADH can cause _ volemic hyponatremia
SIADH can cause euvolemic hyponatremia
First line treatment for DI is _
First line treatment for DI is fluid administration
* In more severe cases, IV hydration may be needed
* Synthetic ADH can be used
Synthetic ADH like _ can be given in cases of DI
Synthetic ADH like desmopressin can be given in cases of DI
The first line therapy for SIADH is _
The first line therapy for SIADH is fluid restriction
* ADH antagonists can also be given
_ can be given to restore sodium in patients with SIADH
Hypertonic saline can be given to restore sodium in patients with SIADH
The most common cause of excess GH is _
The most common cause of excess GH is benign pituitary adenoma
Benign pituitary adenomas are associated with which risk factors?
Benign pituitary adenomas are associated with:
* MEN-1 (multiple endocrine neoplasia)
* McCune Albright syndrome
* Familial isolated pituitary adenomas
* GNAS related (oncogene)
Pituitary adenomas are associated with which MEN syndrome?
MEN-1
Pseudoacromegaly is a condition in which an individual has features of acromegaly but shows no change in GH or IGF-1 axis; what can cause this?
Causes of pseudoacromegaly:
* Medication-induced insulin resistance
* Minoxidil
* Phenytoin
* Hypothyroid
Why might medication induced insulin resistance cause pseudoacromegaly?
Insulin and GH normally oppose each other; without insulin, GH is left uninhibited
Three medication options for GH excess include _ , _ , _
Three medication options for GH excess include octreotide, pegvisomant, cabergoline
