Endocrine Flashcards
Endocrine secretes to…
Distant Sites
Paracrine secretes to…
Adjacent sites
Autocrine secretes to…
At origin
Intracrine secretes to…
Within origin
The pancreas controls what hormones?
Insulin, glucagon, & amylin
The pituitary gland controls what hormones?
GH, ACTH (adrenocorticotropic hormone), Oxytocin, ADH (vasopressin), Prolactin, LH, & FSH (follicle-stimulating hormone)
The hypothalamus controls what hormones?
GnRH (gonadotropin hormone-releasing hormone), Dopamine, CRH (corticotrophin-releasing hormone), GHRH (growth hormone-releasing hormone), & Somatostatin
The thyroid controls what hormones?
Thyroxine, Triiodothyronine, & calcitonin
The adrenal gland controls what hormones?
Epi, Norepi, aldosterone, cortisol, & sex steroids
The parathyroid controls what hormone?
PTH (parathyroid hormone)
What do endocrine hormones do when they initially bind to membrane receptors?
- Initiate signal transduction
- Activate cellular 2nd messengers
- Regulate gene expression
Name 3 ways in which endocrine hormones can be dysfunctional
- Excess
- Deficiency
- Resistance
What is the main determinant of homeostasis?
Hypothalamus
What happens when hormones are released to a receptor?
They travel to pituitary gland and bind G-protein, which then activates adenyl cyclase, which then increases cAMP, then releases secretory hormones
The anterior of the pituitary releases what hormones?
Growth Hormone (bulk)
Adrenocorticotropic
Thyroid-Stimulating
Prolactin
LH &FSH
Beta-lipotropin
The posterior side of the pituitary gland releases what?
Vasopressin & Oxytocin
Which hormone is the most abundant?
GH
GH especially stimulates
Skeletal growth, but stimulates all tissues
How does GH enhance metabolic effects?
- Protein synthesis
- Lypolysis & mobilization of free fatty acids
- Na & H2O retention
- Antagonism of insulin & increased glucose availability
How is GH stimulated?
Stress, sleep, hypoglycemia, & fasting
How is GH inhibited?
Pregnancy, hyperglycemia, cortisol, & obesity
Adrenocorticotropic Hormone (ACTH) regulates…
Secretion of cortisol & androgens
When is ACTH the highest & at its lowest?
AM
PM
What stimulates ACTH?
Stress
Sleep-wake transition
Hypoglycemia
Alpha agonist
Beta antagonist
CRH & decreased cortisol
What inhibits ACTH?
Increased cortisol
Opioids
Etomidate
Suppression of the HPA Axis
When is cortisol needed?
In times of physical stress, illness, or surgery
Decreased cortisol will cause the body to have…
Low BP, glucose, Na
High blood potassium
MOA of Alpha-2 agonist
Stimulate presynaptic α2-adrenergic receptors in the CNS → dilates peripheral blood vessels → lowers peripheral resistance → reduces blood pressure
MOA of Beta-adrenergic blockers/Beta antagonists
Block β receptors → prevent catecholamines (norepinephrine and epinephrine) from binding and activating them → decrease cardiac contractility, decrease conduction velocity through AV node, decrease heart rate, cardiac output, and blood pressure
Role of Thyroid Stimulating Hormone (TSH)
Accelerates thyroid hormone formation
When is TSH stimulated?
When there are low levels of T3, T4, & calcitonin
When is TSH inhibited?
Stress, surgery, SNS stimulation, or increased corticosteroids
Where is vasopressin produced & transported?
Produced in hypothalamus & transported in secretory granules
Where is the reservoir for vasopressin?
The posterior pituitary is the reservoir for release
What is the physiologic function of vasopressin?
Vasoconstriction
Water retention
Corticotropin secretion
When is vasopressin stimulated?
HOTN
Increased plasma osmolarity
Hyperthermia
N/V
Opioids
When is vasopressin inhibited?
Decreased Osmolarity
Cortisol
Hypothermia
Ethanol
Alpha agonists
Macroadrenomas often create a mass effect and cause functioning issues which is…
Overproduction of hormnoes
With macro adenomas, which hormone secretion is treated medically?
Prolactin
in acute surgery 9pituitary tumor removal), which glucocorticoid will the surgeon ask you to administer?
Hydrocortisone or methylprednisolone
What treats GH deficiency?
Recombinant growth hormone
What are the adverse effects of Recombinant growth hormone?
Edema, Myalgia, & arthalgias
Recombinant growth hormone interacts with
Corticosteroids & insulin, decreasing their effectiveness
Octreotide is what type of medication?
Somatostatin analogue
Octreotide inhibits…
GH release & treats acromegaly & acute upper GIB by decreasing blood floe and gastric acid secretion
Adverse effects of Octreotide
Edema, hyperglycemia, bradycardia, nausea, & increases QTc
What is the purpose of administering Cosyntropin?
Cosyntropin, a synthetic ACTH, is used to screen for adrenocortical insufficiency and increases cortisol release
Why isn’t cosyntropin given as a treatment?
Because it would increase release of ALL adrenal hormones
Where is melatonin secreted?
Pineal Gland
How is melatonin secreted and what does it regulate?
Stimulated by darkness & regulated circadian rhythm & sleep mood; may regulate reproduction, tumor growth, & aging; may improve delirium
Vasopressin can be used to treat…
Central DI in neurotrama, pituitary & hypothalamic surgery, cerebral malignancy, ischemia, excess water loss w/ hypernatremia, HOTN, shock, cardiac arrest, excessive blockade of RAAS
Vasopressin works on what receptors?
V1 & V2 receptor agonists
When are plasma vasopressin concentrations decreased?
In sepsis
What is a selective V2 agonist?
Desmopressin (DDAVP)
MOA of DDAVP (V2 agonist)
It activates Gs stimulatory protein, which activates adenyl cyclase, increasing cAMP in collecting ducts cells, increasing exocytosis of vesicles containing aquaporins (intense antidiuretic effect)
DDAVP can cause endothelial cells to release…
von Willebrand factor, which can treat hemophilia A, von Willebrand, & liver disease
What does can be given of DDAVP prior to surgery?
0.3mcg/kg IV 30min. prior to a patient who is deficient in von Willebrand factor & factor 8
MOA of Vasopressin (V1 receptor)
Activates stimulatory Gq protein, which activates phospholipase C, increasing IP3, which increases intracellular Ca+ release
All causing intense vasoconstriction, myocardial hypertrophy, platelet aggregation, & ACTH release
Dose of Vasopressin
1-4 units (bolus)
0.01-0.04 units/min infusion
Adverse effects of vasopressin
Coronary ischemia
Angina
Dysrhythmias
Splanchnic & peripheral ischemia
Increased GI peristalsis, leading to N/V & ABD pain
Uterine stimulation
Allergic reaction & anaphylaxis
Antibody formation w/long-term use
May decrease platelet count
MOA of oxytocin
Increases intracellular calcium in uterine smooth muscle, which causes uterine muscle contraction
Causes contraction of the myoepithelial cells around milk-containing alveoli, resulting in milk ejection during lactation
Induces labor, reducing & preventing uterine atony
Reduces blood loss
Labor dose of oxytocin
8-10mU/min IV