Endocrine Flashcards
Which adrenal gland goes to the renal vein before the IVC?
Left adrenal gland (same as gonadal vein)
Which anterior pituitary hormones are basophils?
B-FLAT
Basophils - FSH, LH, ACTH, TSH
What type of receptors are insulin receptors?
Tyrosine kinase receptors
How does insulin affect the following? Na+: TGs: K+: Amino acids:
Sodium retention increased in the kidneys
Triglyceride synthesis increased
Cellular uptake of potassium and amino acids increased
Which GLUT receptor is in the brain?
GLUT-1: RBCs, brain, cornea
What aside from glucose increases insulin release?
β2-agonists and Growth Hormone (increases insulin resistance)
How does prolactin influence GnRH?
Decreases GnRH release
How does TRH affect prolactin?
TRH increases prolactin
What enzymes are used to produce aldosterone from cholesterol?
- Cholesterol desmolase
- 3β-hydroxysteroid dehydrogenase
- 21-hydroxylase
- 11β-hydroxylase
- Aldosterone synthase
What enzyme is necessary to produce cortisol and sex hormones? What happens when this enzyme is deficient (For XX and XY individuals)?
17α-hydroxylase
XX: lack secondary sexual development
XY: pseudohermaphroditism (ambiguous genitalia and undescended testes)
What are the functions of cortisol? (BIG FIB)
Blood pressure increase (upregulates α1 receptors on arterioles)
Insulin resistance (diabetogenic)
Gluconeogenesis, lipolysis and proteolysis are increased
Fibroblast activity is DECREASED
Inflammatory and immune responses are DECREASED
Bone formation (osteoblast activity) is DECREASED
RANK-L (production induced by PTH) binds RANK on _______ leading to _______ stimulation
RANK-L (production induced by PTH) binds RANK on OSTEOBLASTS leading to OSTEOCLAST stimulation
How does Magnesium affect PTH secretion?
Low serum magnesium causes increased PTH secretion
Very low serum magnesium causes decreased PTH secretion
Which endocrine hormones work via a cAMP pathway?
FLAT CHAMP
FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2), MSH, PTH
Which endocrine hormones work via an IP3 pathway?
GOAT HAG
GnRH, Oxytocin, ADH (V1 receptor), TRH, Histamine, Angiotensin II, Gastrin
Which endocrine hormones use an intrinsic tyrosine kinase receptor? (MAP kinase pathway)
Insulin, IGF-1, FGF, PDGF, EGF
What are the functions of T3? (4 Bs)
Bone growth
Brain maturation
Beta adrenergic effects (increase CO, HR, SV, contractility)
Basal metabolic rate increase (via increased Na+/K+ ATPase)
What is the Wolff-Chaikoff effect?
Excess iodine temporarily inhibits thyroid peroxidase causing decreased iodine organification and decreased T3/T4 production
What enzyme converts T3 to T4 in the periphery?
5’-deiodinase
From what cells is a neuroblastoma/pheochromoblastoma derived?
Neuroblastoma: Neural crest cells
Pheochromocytoma: Chromaffin cells (derived from neural crest cells)
What gene is overexpressed in a neuroblastoma? What is seen in the urine? What is seen on histology?
N-myc oncogene is overexpressed
Homovanillic acid (a breakdown product of dopamine) is increased in urine
Homer-wright rosettes seen on histology
What is the rule of 10s for pheochromocytoma?
10% malignant 10% bilateral 10% extra-adrenal 10% calcify 10% kids
What is seen in the urine in a pheochromocytoma?
VMA - Vanillymandelic acid (breakdown product of NE and Epi)
How does hyperthyroidism affect cholesterol and through what mechanism?
Causes hypocholesterolemia due to increased LDL receptor expression
Which HLA is associated with Hashimoto’s thyroiditis?
What disease are patients at increased risk for with Hashimoto’s thyroiditis?
HLA-DR5; non-Hodgkin lymphoma
What are the “6 Ps” of congenital hypothyroidism (cretinism)?
Pot-bellied Pale Puffy-faced child Protruding umbilicus Protuberant tongue Poor brain development
What type of thyroiditis occurs when the thyroid is replaced by fibrous tissue (manifestation of IgG4-related systemic disease)?
Riedel thyroiditis
De Quervaine thyroiditis is (painful/painless)
Riedel thyroiditis is (painful/painless)
De Quervaine thyroiditis is PAINFUL
Riedel thyroiditis is PAINLESS
What is a toxic multinodular goiter? What is the Jod Basedow phenomenon for toxic multinodular goiters?
Hyperfunctioning follicular cells working independently of TSH due to mutation in TSH receptor
JB: Thyrotoxicosis if a patient with iodine deficiency goiter is made iodine replete
How is a thyroid storm treated (3 Ps)
Propranolol (β-blockers) , Propylthiouracil, Prednisolone (corticosteroids)
What artery is at risk of transection in a thyroidectomy?
Inferior thyroid artery
Which thyroid cancer is associated with psammoma bodies, orphan annie eye nuclei, and RET and BRAF mutations?
Papillary carcinoma (excellent prognosis)
Which thyroid cancer is associated with MEN2A and 2B mutations, produces calcitonin, and displays sheets of cells in an amyloid stroma?
Medullary carcinoma
What is osteitis fibrosa cystica caused by? What are the symptoms of this disease?
Primary hyperparathyroidism
Stones (renal), Bones (bone pain), Groans (Weakness and constipation - acute pancreatitis), and psychiatric overtones (depression)
What are Chvostek sign and Trousseau sign in hypoparathyroidism?
Chvostek sign: Tapping of facial nerve causes contraction of facial muscles
Trousseau sign: Occlusion of brachial artery with BP cuff causes carpal spasm
What is pseudohypoparathyroidism and what is a unique finding?
Autosomal dominant unresponsiveness of kidney to PTH
Shortened 4th and 5th digits
What is the most common cause of death in children with gigantism?
Cardiac failure
What 2 tests is used to diagnose acromegaly?
Failure to suppress serum GH following oral glucose tolerance test and Increased serum IGF-1 levels
How does the body maintain near normal volume status in SIADH?
Body responds to water retention with decreased aldosterone (leads to hyponatremia)
What is the purpose of the HbA1c test in diabetes mellitus?
Reflects average blood glucose over prior 3 months
Which type of diabetes has a stronger genetic predisposition?
Diabetes Type 2 (90% concordance in identical twins)
What happens to potassium during diabetic ketoacidosis?
Hyperkalemia, but depleted intracellular K+ due to transcellular shift from decreased insulin
What is the Whipple triad (associated with insulinoma CNS effects)?
Lethargy, syncope, diplopia
What diseases are associated with MEN1
Pituitary, Parathyroid, and Pancreatic tumors
What diseases are associated with MEN2A?
Parathyroids
Pheochromocytoma
Medullary Thyroid carcinoma
What diseases are associated with MEN2B?
Medullary thyroid carcinoma
Pheochromocytoma
Oral/Intestinal ganglioneuromatosis
What are the functions of amylin analogs (Pramlintide)?
Decreased gastric emptying
Decreased glucagon
What are the functions of GLP-1 analogs (Exenatide, Liraglutide)?
Increase insulin
Decrease glucagon release
What are the functions of DDP-4 Inhibitors (Linagliptin, Saxagliptin, Sitagliptan)?
Increase insulin
Decrease glucagon release
*Block the degradation of GLP-1 analogs
What is the adrenal cortex derived from?
What is the medulla derived from?
Cortex: Mesoderm
Medulla: Neural crest
What drugs can cause nephrogenic diabetes insipidus?
What drug can cause SIADH?
NDI: Lithium and Demeclocycline (treatment for SIADH)
SIADH: Cyclophosphamide
By what mechanism does hyperthyroidism increase basal metabolic rate? Sympathetic nervous system activity?
BMR: Increased synthesis of Na+/K+ ATPase
SNS activity: Increased expression of Beta1 adrenergic receptors
What transports oxytocin and vasopressin from the hypothalamus to the posterior pituitary?
neurophysins
Where are β cells located in the pancreas? α cells? What does each produce?
β cells (insulin producing) are central and α cells (glucagon) are peripheral
CRH increases what three hormones?
ACTH, MSH, and β-endorphins
What increases somatomedin? What does somatomedin cause?
Growth hormone (somatotropin) increases somatomedin which increases somatostatin which suppresses growth hormone release
How does cortisol affect IL-2 and histamine release?
Blocks IL-2 production (can lead to reactivation of candidiasis and TB) and blocks histamine release from mast cells
Which endogenous hormone increases production of macrophage colony-stimulating factor?
PTH
How does pH affect calcium levels?
Increase in pH → increased affinity of albumin (negative charge) to bind calcium → clinical manifestations of hypocalcemia (cramps, pain, paresthesias)
Which endocrine hormones use a receptor associated tyrosine kinase (JAK/STAT)? (PIG)
Prolactin, Immunomodulators (cytokines and interleukins), Growth hormone
Why are sodium levels normal in primary hyperaldosteronism (Conn syndrome or adrenal hyperplasia)?
Aldosterone escape: Secretion of ANP to prevent hypernatremia
How is primary adrenal insufficiency distinguished from secondary adrenal insufficiency?
secondary adrenal insufficiency has no skin/mucosal hyperpigmentation and no hyperkalemia
Where can a neuroblastoma occur and how is it differentiated from Wilms tumor?
Neuroblastomas can occur anywhere along the sympathetic chain
Presents as a firm, irregular mass that can cross the midline vs. Wilms tumor which is smooth and unilateral
Increased cAMP in urine is most likely due to…
Primary hyper-parathyroidism (PTH works through Gs pathway)
What is pegvisomant?
Growth hormone receptor antagonist
How does T2DM lead to nephrotic syndrome? Blindness?
Nephrotic syndrome: NEG → hyaline arteriorsclerosis → preferential involvement of efferent arterials → glomerular hyperfiltration → microalbuminuria → nephrotic syndrome
Blindness: Glucose freely enters schwann cells → aldose converts glucose to sorbitol → osmotic damage → neuropathy → blindness
