L1- Basics

Question 1

Describe the morphology of classic endocrine ducts.

Answer 1

Classic endocrine glands are ductless (and therefore have to be highly vascularized)- main feature

They secrete hormones directly into the blood stream or extracellular space.

The entire organ is dedicated primarily to endocrine function.

Question 2

What is the main non-classic endocrine organ of the brain?

Answer 2

The hypothalamus

Question 3

What hormones are released by the kidney (a non-classical endocrine organ)?

Answer 3

Renin, Vitamin D (in its active form), erythropoietin (EPO)

Question 4

What hormones are released from the heart (a non-classical endocrine organ)?

Answer 4

Atrial/Brain natriuretic peptide (ANP/BNP)

Question 5

What hormones are released from the liver (a non-classical endocrine organ)?

Answer 5

Insulin-like growth factor (IGF-1)

Question 6

What hormones are released from the GI tract (non-classical)?

Answer 6

serotonin and ghrelin

Question 7

What hormones are released from adipose tissue (non-classical endocrine organ)?

Answer 7

Leptin

Question 8

Differentiate a primary endocrine defect from a secondary/tertiary defect

Answer 8

Primary: problem with the endocrine gland

Secondary/tertiary: problem elsewhere

Question 9

Endocrine pathologies are characterized by what?

Answer 9

Hormone imbalances

Question 10

What is the timing of the onset of symptoms of most endocrine disorders?

Answer 10

Slow- symptoms can take a long time to develop and may seem unrelated

Question 11

Describe cretinism

Answer 11

Congenital disorder due to iodine deficiency during development- presents as short stature, impaired bone formation, mental retardation and delayed motor development

Question 12

What is the etiology of multiple endocrine neoplasia? WHat is it?

Answer 12

MEN: genetic

Characterized by 2-3 tumors in multiple endocrine glands (pituitary, parathyroid, entero-pancreatic

Question 13

Type 1 diabetes is what type of disorder?

Answer 13

autoimmune

Question 14

What is Sheehan’s syndrome?

Answer 14

Post-partum hemorrhage/shock that results in massive pituitary death

Question 15

What is the most common endocrine pathology?

Answer 15

Diabetes mellitus Type II- everyone is fat now.

Question 16

What is the purpose of hormone binding proteins?

Answer 16

Hormone binding proteins bind to hormones in the blood to facilitate transport. This generally increases the half-life of hormone in the blood.

Question 17

Are hormone binding protein-bound hormones bioavailable?

Answer 17

No

Question 18

What types of hormones are generally bound by hormone binding proteins?

Answer 18

Steroid hormones (which are lipophilic)

IGF-1, GH, T4/T3

Question 19

What nonspecific binding hormones carries many different hormones through the blood?

Answer 19

Albumin

Question 20

Discuss the relative amount of bound/unbound sex hormones in the blood

Answer 20

Nearly all of the sex hormones are bound by either SHBG or albumin in the blood

Question 21

How are “bound” hormones delivered to the cell?

Answer 21

1) The hormone may be released at the membrane and freely diffuse across the membrane (steroid hormones)
2) Hormone/binding protein complex binds to megalin on the outside of the cell and enters via endocytosis

Question 22

Discuss the specificity and affinity of hormone/receptor binding.

Answer 22

Hormones bind their receptors with high specificity and high affinity

Question 23

Where do lipophobic hormones bind? How do they signal?

Answer 23

Lipophilic hormones bind to cell surface receptors. They signal through secondary messenger systems like IP3/DAG and cAMP

Question 24

What is the lifespan of a lipophobic hormone?

Answer 24

They are rapidly internalized or degraded

Question 25

Describe the intrinsic catalytic activity of receptor-linked kinases

Answer 25

Receptor-linked kinases do NOT have intrinsic activity- ligand binding causes dimerization, which then activates intracellular kinase activity

Question 26

Give 3 examples of hormones that act via receptor-linked kinases

Answer 26

Growth hormone, prolactin and EPO

Question 27

Describe the intrinsic catalytic properties of receptor kinases

Answer 27

Receptor kinases have intrinsic kinase activity- they are activated by ligand binding

Question 28

Name two hormones that act via receptor kinases

Answer 28

Insulin and ANP

Question 29

Discuss the mechanism of action of lipophilic hormones

Answer 29

Lipophilic hormones can cross the cell membrane and act via hormone receptors (usually as transcription factors, which are previously bound in the cell via chaperones)