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
Atony dose of oxytocin
1-5 International units IV bolus over 30sec
Adverse Effects of Oxytocin
Direct vascular smooth muscle relaxation
Transient decrease in SBP/DBP, venous return & CO
Reflex Tachy & arrhythmia
Higher risk w/anesthetic-induced blunting or compensatory reflex mechanism
Higher risk in hypovolemia
Adverse effects of Oxytocin in relation to fetus & neonate
Fetal hypoxia & hypercapnia
Variable decelerations of fetal HR
Neonatal jaundice & seizure
Low Apgar score
What are the 3 pancreas cells
Alpha, beta, & delta
What does the pancreas secrete?
Digestive substances into duodenum (exocrine)
Secrete insulin, glucagon, somatostatin & pancreatic polypeptide (Endocrine)
Alpha cells & glucagon are what percent of islet cells and secrete what hormone?
25%
Catabolic hormone
The catabolic hormone released in alpha cells do what?
Mobilizes glucose fatty acids & amino acids for use
Metabolized by liver w/ 1/2 time 3-6min
In the alpha cells, catabolic hormone is stimulated by
Hypoglycemia
Stress, trauma
Beta Agonists
Acetylcholine
Cortisol
In alpha cells, catabolic hormone is decreased by
Hyperglycemia
Free fatty acids
Insulin & somatostatin
Alpha agonists
In Beta cells with glucagon, glucagon binds ______&_______ receptors
Glucagon & GLP-1
In Beta cells with glucagon, binding of glucagon & GLP-1 receptors causes…
- Activation of adenyl cyclase
- Increases cAMP
- Modulates insulin release
Beta cells & insulin account for what percentage of islet cells?
60%
In Beta cells, Insulin is a ________hormone, which promotes________
Anabolic (builds up) hormone
Promotes storage of glucose, fatty acids & amino acids
Hepatic& renal metabolism with 1/2 time 5 min
In Beta cells with insulin, the anabolic hormone is stimulated by…
Hyperglycemia
Beta Agonist
Acetylcholine
Glucagon
In Beta cells, anabolic hormone is decreased by…
Hypoglycemia (inhibits K+ channels)
Beta Antagonoists
Alpha antagonists
Insulin & somatostatin
Volatile Anesthetics
Thiazide diuretics
Glucose & Insulin relationship
Uptake & use promoted
Increases activity of glucokinase
Increases permeability of skeletal muscle
Fat & insulin relationship
Increases storage in adipose
Inhibits lipase (lipolysis)
Protein & Insulin relationship
Increases uptake & conservation of amino acids
Decreases degradation
Delta cells & Somatostatins account for______of islet cells
5%
Somatostatin, a ______hormone does the following:
Inhibitory hormone
Regulates islet cell secretion
Inhibits insulin & glucagon release
Inhibits gallbladder contraction, gastric motility & splanchnic blood flow
Characteristics of Type I DM
Autoimmune
Destruction of pancreatic beta cells
Normal insulin sensitivity
Characteristics of Type II DM
Pancreatic beta cell dysfunction
Failure to secrete insulin & insulin resistance
May/may not need insulin
What causes the release of insulin
Released in response to increase in serum glucose
Insulin promotes
Glucose uptake by fat & muscle
Insulin inhibits
Gluconeogenesis
Glucogenolysis
Insulin is a/an ________ hormone that promotes building of macromolecules and__________________________
Anabolic hormone
Storage & uptake of fats & glucose
Patients with Type 2 DM will have issues with_________at the cellular level
Translocation
At the cellular level, insulin is increased by
Beta-adrenergic or PSNS stimulation
At the cellular level, insulin is decreased by
Alpha adrenergic stimulation
How many units of insulin are secreted per day?
40
What is the reservoir of insulin?
Skeletal muscle & adipose tissue
How long does it take insulin to work
30-60 minutes
Insulin relationship in liver & kidney
Enzymatic metabolism ini liver & kidney with an elimination 1/2 time of 5-10 min
Prolonged effects ini renal disease
What happens in the absence of insulin?
Lipolysis & increase in fatty acids
Excess ketones
Acidosis
What happens when insulin is low or when there is insulin resistance?
Hyperglycemia will cause:
Proinflammation
Prothrombotic
Proatherogenic
Impaired vasodilation
DM on the macrovascular side will cause
Coronary issues like HF & death
Cerebrovascular effects like stroke
PVD
DM on the microvascular side will cause
Neuropathy (issues w/conduction)
Nephropathy, leading to ESRD
Retinopathy (cause of blindness)
The surgical stress response will causes_______& the release of _______
Neuroendocrine stress response
Release of epi, glucagon, cortisol, GH, & inflammatory cytokines
Risks of Neuroendocrine stress response include
Acute insulin resistance & impaired secretion
Decreased peripheral glucose utilization
Lipolysis
Protein catabolism
Hyperglycemia
What in crease your chances of having a surgical stress response?
GA, type of surgery, & additional factors such as sepsis, inflammation, or glucocorticoid use
Which labs should the NAP student assess?
FSBS, renal, A1C
Risks of neuropathy include
CV instability
Delayed Gastric emptying
OSA
Increased sensitivity to LA
Increased sensitivity to LA can cause
Losses in sensation
Increased risk of nerve damage
Prolonged duration of action
Slow, long acting insulin include
NPH, insulin glargine & insulin detemir
Rapid, short acting insulin includes
Insulin aspart, Lispro, & Glulisine
Insulin receptors are fully saturated at ______concentrations
Low (tight binding)
Lispr o& insulin aspart are usually given
30-60 min before meals with a duration of 3-5 hours
NPH is ________acting and is conjugated with_________
Intermediate acting
Protamine (developed sensitivity with long term use)
Glargine & detemir are _____acting and are usually administered at _______
Long
Night (basal replacement for 24 hours)
Which insulin therapy should be decreased by 50% before surgery?
NPH, glargine & detemir
Regular insulin is used to treat
Abrupt onset of hyperglycemia & ketoacidosis
IV onset of regular insulin?
SQ?
IV 10-15min
SQ 30-60min
When should SQ insulin be avoided?
In hemodynamically unstable patients, hypothermia, & vasoconstriction
What is the duration of IV & SQ insulin?
2-8 hours
Does insulin bind to IV tubing?
Yes
Goal of serum glucose
<180
>70
Things to consider with SQ insulin correction
Surgery <4hours
They are hemodynamically stable w/minimal fluid shift
Not dosing more than Q2h
Monitor at leaast Q2h
Consider dose reduction in sensitive populations such as >70yrs, renal insufficiency, & no hx of DM
Things to consider with continuous insulin infusion
Surgery >4hrs
Hemodynamic fluctuations
Use of inotropes
Massive fluid shift or temperature changes
Critically ill
Cardiac surgery
Interventions when given Insulin continuously
Allows for rapid dose adjustments
Monitor BS hourly
Monitor K+ & HCO3-, Ca+
Do not abruptly stop
Types of correctional insulin combinations that can be given
Insulin I& glucose t prevent hypoglycemia
Glucose-Insulin-Potassium (GIK) infused at 100ml/hr
An insulin pump provides
Continued basal insulin, that should be monitored hourly & should be turned off is BS<110 and given additional insulin if BS<180
Adverse effects of Insulin
Hypoglycemia
Hypokalemia
Allergic reaction/injection site reactions
Insulin resistance (acute)
Signs of hypoglycemia
Tachycardia
Diaphoretic
HTN
Confusion
Seizures
Hypoglycemia can be corrected with IV dextrose at
IV dextrose 5-25g
Onset <10min
How should IV dextrose be given
Large PIV
Central Line
Administer slowly
Flush
IV glucagon is a
Treatment for hypoglycemia
Insulin antagonist
Dose 0.5-1mg
Dilute w/sterile water
Also relaxes GI smooth muscle
Insulin stimulates the _____pump and you should monitor for_______
NaK pump
Monitor for hypokalemia with insulin therapy
How to treat hyperkalemia
Insulin + Dextrose (will temporarily shift K+ back into cell within 15min & lasts 2hrs
5-10 units IV insulin
25-50 g dextrose UNLESS hyperglycemia >200
What is the first line treatment of Type II
Metformin, which is apart of the Biguanide class
Does metformin cause hypoglycemia?
Rarely
MOA of metformin
Suppression of hepatic glucose production
Decreases GI glucose absorption
Increases insulin sensitivity by peripheral tissues
Increases GLP-1 synthesis
Adverse effects of Metformin
GI* (nausea, anorexia, diarrhea)
VIT B12 deficiency
Lactic Acidosis
High risk of hepatic or renal dysfunction
When to give/hold metformin
Give in ambulatory surgery/minor cases, but hold for renal dysfunction, use of contrast/NSAIDS ACEI or ARBS
Hold day of for major surgery & restart w/in 24 hours
MOA of sulfonylureas
Inhibit K+ ATP channels on beta cells (sulfonylurea receptor 1), causing Ca+ to enter cell and exocytosis of insulin
Sulfonylureas require____& have a high risk of_____
Beta cell function
High risk of therapy failure
Benefit of Sulfonylureas
Can drastically lower BS and decrease insulin resistance
Ineffective in Type I
Examples of Sulfonylureas
Glyburide
Glipizide
Glimepiride
Chlorpropamide
Adverse effects of Sulfonylureas
Hypoglycemia
CV risks (older drug)
GI issues
Abnorm liver function
Hypoglycemia with Sulfonylureas is most common with what risks?
Drugs w/long half times
Malnutrition
> 60yrs
Impaired renal function
ETOH, warfarin, sulfonamide abx, or other drug interaction
More severe than insulin-induced hypoglycemia
Examples of Thiazolidinediones (TZDs)
Rosiglitazone
Pioglitazone
MOA of Thiazolidinediones (TZDs)
Increases insulin sensitivity at skeletal muscle, hepatic & adipose tissue, which decreases insulin resistance & hepatic glucose production
Increases glucose use by tissues
Thiazolidinediones (TZDs) can also
Increase HDL, decrease triglycerides
Increase ECF (edema, wt gain)
Cause liver dysfunction
Should be continued preoperatively
GLP-1 Receptor Agonists examples include
-glutides
Tirzepatide
Exenatide
MOA for GLP-1 Receptor Agonists
Increase beta cell insulin secretion & satiety
Decreased alpha cell glucagon production & appetite
Slow gastric emptying
Wt loss
Adverser effects of GLP-1 Receptor Agonists
GI issues (N/V/D)
Hypoglycemia risk when combined w/sulfonylurea & insulin
Acute pancreatitis
Gallbladder & biliary disease risk (cholecystitis)
Acute renal insufficiency
Injection site reaction
Delayed gastric emptying
MOA for Sodium-Glucose Cotransporter 2 inhibitors
Inhibits SGLT2 in proximal tubule
Requires normal renal function
Examples of Sodium-Glucose Cotransporter 2 inhibitors
-gliflozins
Sodium-Glucose Cotransporter 2 inhibitors can cause
Wt loss
Reduce BP
Reduce CV events
Adverse effects of Sodium-Glucose Cotransporter 2 inhibitors
Osmotic Diuresis due t trapping of glucose, causing hypovolemia, HOTN, AKI (higher risk in ACEI & ARBS
Euglycemia (norm BS) ketoacidosis
UTI & genital nifections
Reduced bone density
Sodium-Glucose Cotransporter 2 inhibitors considerations
Risk for ketoacidosis & dehydration
Hold morning of-days
Restart w/adequate PO intake
MOA of Dipeptidyl-Peptidase-4 inhibitors
Inhibits DPP-4 enzyme which breaks down incretini hormone (GLP-1), which increases insulin secretion & decreases glucagon secretion (increases GLP-1)
Examples of Dipeptidyl-Peptidase-4 inhibitors
-gliptin
Risks associated with Dipeptidyl-Peptidase-4 inhibitors
Musculoskeletal pain & pancreatitis
Hypoglycemia risk low
Should Dipeptidyl-Peptidase-4 inhibitors be continued or held?
Continued perioperatively
