L1 Intro to Endocrine Pharmacology

Question 1

3 classes of hormones

Answer 1

1. Peptide/protein hormones
2. Steroid hormones
3. Amino acid-based hormones

Question 2

Briefly describe how the endocrine system works

Answer 2

• uses chemical messengers (hormones) to coordinate many aspects of physiology
• releases hormones into bloodstream where they’re transported to every cell in the body
• hormones will only affect cells that have receptors specific to that hormone
• hormones can affect many different cells and tissues at once

Question 3

Can a cell contain receptors for many different hormones?

Answer 3

Yes

Question 4

4 types of hormone receptors

Answer 4

1. Ligand-gated ion channels (ionotropic receptors)
2. G-protein coupled receptors (GPCRs)
3. Kinase-linked receptors
4. Nuclear receptors

Question 5

Why do both kinase-linked receptors and nuclear receptors take longer to initiate a response after hormone binding?

Answer 5

Because they are dependent upon transcription and protein synthesis

Question 6

Which hormone receptors are most commonly involved in hormone/receptor binding?

Answer 6

Kinase-linked receptors

Question 7

Where can hormone receptors be located?

Answer 7

cell membrane, cytosol, nucleus

Question 8

Peptide/protein hormones are secreted by?

Answer 8

• anterior and posterior pituitary gland
• pancreas
• parathyroid gland

Question 9

Synthesis of peptide/protein hormones

Answer 9

• synthesised on rough ER, first as large proteins (preprohormones) which are cleaved to form prohormones in ER
• prohormones transferred to Golgi apparatus for packaging in secretory vesicles, then cleaved to form active hormones
• stored in secretory vesicle until needed

Question 10

Why can’t peptide/protein hormones get across the cell membrane to bind nuclear receptors?

Answer 10

because they are water soluble

Question 11

Steroid hormones are secreted by?

Answer 11

• adrenal cortex
• ovaries
• testes
• placenta

Question 12

Most steroid hormones are synthesised from?

Answer 12

cholesterol

Question 13

Structure of steroid hormones

Answer 13

consist of 3 cyclohexyl rings and one cyclopentyl ring combined in a single structure

Question 14

Are steroid hormones stored?

Answer 14

No, they are synthesised as needed

Question 15

Steroid hormones are __ soluble.

Answer 15

lipid

Question 16

Steroid hormones circulate in the blood mainly bound to __.

Answer 16

plasma proteins
(only ~10% exist free in plasma)

Question 17

What do protein-bound steroid hormones act as?

Answer 17

Act as a store to replenish free hormones (since they cannot readily cross lipid membranes)

Question 18

Amino hormones are secreted by?

Answer 18

• thyroid
• adrenal medullae

Question 19

Amino hormones are derived from __.

Answer 19

tyrosine

Question 20

Amino acids are formed by?

Answer 20

the action of enzymes in the cytoplasmic compartment of glandular cells

Question 21

Where are thyroid hormones stored?

Answer 21

in macromolecules of the protein thyroglobulin

Question 22

Where are adrenal medullary amino hormones stored?

Answer 22

in secretory vesicles until needed

Question 23

Hormone receptors mediate cellular changes after binding via regulation of…

Answer 23

• ion channels
• regulatory proteins
• enzymes
• gene activation

Question 24

Melatonin released from pineal gland binds to which type of receptor?

Answer 24

GPCR

Question 25

CRH released from hypothalamus binds to which type of receptor?

Answer 25

GPCR

Question 26

GH released from pituitary gland binds to which type of receptor?

Answer 26

Kinase-linked receptor

Question 27

ACTH released from pituitary gland binds to which type of receptor?

Answer 27

GPCR

Question 28

Triiodothyronine released from thyroid gland binds to which type of receptor?

Answer 28

Nuclear receptor

Question 29

PTH released from parathyroid gland binds to which type of receptor?

Answer 29

GPCR

Question 30

Corticoids and adrenaline released from adrenal gland bind which type of receptors?

Answer 30

Nuclear receptor and GPCR, respectively

Question 31

The pancreas secretes insulin and glucagon. To which receptor types do these hormones bind?

Answer 31

Kinase-linked receptor and GPCR, respectively

Question 32

To which receptor type do oestrogen, progesterone and testosterone bind?

Answer 32

nuclear receptor

Question 33

3 mechanisms of endocrine disease

Answer 33

1. Hormone deficiency - insufficient stimulation from pituitary - hypofunction of gland itself - increased clearance of hormones 2. Hormone excess - excessive stimulation from pituitary - hyperplasia or neoplasia of the gland - ectopic hormone production (cancers) 3. Hormone resistance

Question 34

Example of a drug that blocks adrenaline?

Answer 34

beta blocker e.g. atenolol

Question 35

Example of a hormone (and neurotransmitter) that binds a ligand-gated ion channel?

Answer 35

Serotonin (5HT3 receptor)