Endocrinology 1- Basics of Endo

Question 1

Homeostasis

Answer 1

State of equilibrium in body with respect to various functions and to the chemical compositions of the fluids and tissues

Question 2

If something is “Hyper____” what does that mean

Answer 2

Overproduction of a hormone and/or hypersensitivity to hormonal effects

Question 3

if something is “hypo____” what does that mean

Answer 3

Underproduction of a hormone and/or sensitivity to hormonal effects

Question 4

Qualitative disorders vs quantitative disorders

Answer 4

Qualitative woul dbe like a virus - you hve it or not

Quantitative is like an endocrine disorder - you can measure levels

Question 5

Primary symptoms of an endocrine disorer

Answer 5

Weight/appetite changes
fatigue
hair loss/hirsutism
Cognitive (forgetfulness, confusion)
dizziness
moodiess (depression/anxiety/aggression)

Question 6

What would a primary endocrine disorder be?

Answer 6

In a classical endocrine gland (not upstream)

Question 7

Multiple endocrine neoplasia (MEN)

Answer 7

Some drugs cannot be taken up by people who have this defect in the MEN gene (dominant disorder) - Tumors spontaneously arise in endocrine organs, not at the same time

Question 8

Congenital hypothyroidism

Answer 8

Condition where there was an iodine deficiency during development - result is short stature and impaired bone formation, as well as severe cognitive impairment and delayed motor function

Question 9

Sheehan’s Syndrome

Answer 9

Postpartum hemorrhage results in loss of pituitary gland cells —Mikayla I know you do my flash cards, remember this next time you’re having baby fever

Question 10

What is the most common endocrine disorder in the clinic?

Answer 10

Diabetes Mellitus (esp type 2)

Question 11

Classical vs non classical endocrine glands

Answer 11

Classical are ductless - just released directly into the blood (and possibly even into extracellular space for Paracrine effects)

Nonclassical would be specialized cells within organs that make and produce hormones (including things like renin-producing cells)

Question 12

Endocrine means

Answer 12

Hormone is released into the blood and acts on downstream targets

Question 13

Paracrine means

Answer 13

Hormone is released into the interstitial space and acts on nearby targets

Question 14

Autocrine means

Answer 14

Hormone is released into the interstitial space and acts on the cell that released it

Question 15

Factors affecting hormone bioavailability (5)

Answer 15

Hormone target (ex. Binding proteins and kinetics of half life); target tissues (ex. Receptors available and chaperones available); hormone synthesis/release (enzymatic activity, processing, packaging); regulatory mechanisms (such as feedback, circadian rhythm, aging, and pulsitility)

Question 16

What would be ways hormone transport can affect bioavailability of that hormone

Answer 16

Binding proteins (free vs bound) and kinetics of the half life of the protein and metabolism

Question 17

What would be ways that target tissues can affect the bioavailability of a hormone

Answer 17

Receptors - they can have mutations, be desensitized, down or upregulated
Chaperone/heat shock proteins that are responsible for stabilization

Question 18

What are ways in which hormone synthesis and release can impact bioavailability of a hormone?

Answer 18

Enzymatic activity, processing, and packaging

Question 19

What are ways in which regulatory mechanisms can impact bioavailability of a hormone?

Answer 19

Feedback, circadian rhythms, aging, and pulsitility

Question 20

How are hormones typically traveling in the blood?

Answer 20

Bound to something else (although a small portion will be free) — this is ESPECIALLY true if the hormone is lipophilic, but there are some that are peptides that will also do this like T3/T4 and IGF-I

Question 21

What is a benefit of hormones binding to a binding protein?

Answer 21

It greatly increases the half life and in some cases prevents overstimulation of pathways

Question 22

Bioavailable vs active

Answer 22

Hormones must be unbound to be active - however even bound hormones are often “bioavailable” - can be used if necessary

Question 23

Are there sometimes sex difference in bioavailability of a hormone? Explain.

Answer 23

Yes - example is testosterone which can be bound to albumin or free (bioavailable) or bound to SHBG -= highly specific binding protein that is not bioavailable but more like a storage depot, and must be cleaved to access testosterone.

Question 24

How are hormones cleared generally speaking?

Answer 24

Intracellular metabolism, liver metabolism, and urinary/fecal excretion
liver metabolism includes phase I and II (hydroxylation/carboxylation, conjugation) that we talked about in the metabolism lectures

Question 25

Two main scenarios of hormone delivery to target tissue if there is an intracellular receptor for it.

Answer 25

1- steroid hormone is released at membrane and freely diffuses across bilateral and finds intracellular targets.
2- hormone/protein complex binds to megalin, forms an endocytosis vesicle, and hormone dissociates and is released from vesicle to bind to target

Question 26

If there is no receptor for hormone X but lots of hormone X what will happen with regard to the physiological function of that hormone

Answer 26

It won’t happen - without the receptor no message can be conveyed and no response can happen

Question 27

What determines the duration of hormone activity

Answer 27

Receptors

Question 28

Can hormone auto regulate

Answer 28

Yes - ligand can up or down regulate the receptor depending on hormone levels

Question 29

Specificity of a hormone receptor is what?

Answer 29

The ability of a receptor to distinguish between similar substances

Question 30

Affinity with hormone:receptor binding is what?

Answer 30

Measured as Kd, this is the amount of receptor which is bound by a specific amount of ligand.

Question 31

Will the physiological response be the same as the percent of receptors bound by a hormone?

Answer 31

No and in fact many times the physiological response requires a very small portion of the available receptors to be bound at any point in time

Question 32

What are the 3 classes of cell surface receptors hormones may act on?

Answer 32

GPCRs, RTKs, and receptor linked kinases (ex. Growth hormone, prolactin, receptors)

Note that ion channels are NOT hormone receptors

Question 33

Are ion channels a type of hormone receptor

Answer 33

No
The answer is no
This is going to show up on the test
And you better pick no
It’s no
No

Question 34

What is a major exception of a lipophobic protein having an internal receptor

Answer 34

THyroid hormone

Because of course it’s thyroid hormone