Pharmacology

Question 1

define endocrine

Answer 1

ductless glands which secrete hormones

Question 2

define autocrine

Answer 2

acts on self/regulate own secretion

Question 3

define paracrine

Answer 3

acts on nearby cells

Question 4

3 main classes of hormone

Answer 4

proteins/peptides
steroid
tyrosine/tryptophan derivatives

Question 5

features of peptide hormone

Answer 5

enzymatically cleaved from larger proteins
synthesised following RNA translation
hydrophilic
transported free in plasma

Question 6

what does exocytosis from cells depend on

Answer 6

calcium

Question 7

features of steroid hormones

Answer 7

based on cholesterol, which is converted to pregnenolone
this occurs on mitochondrial membrane
not bundled/packaged - released straight into plasma

Question 8

what is the rate limiting step in steroid hormone synthesis

Answer 8

cholesterol conversion to pregnenolone

Question 9

give an example of a tyrosine/tryptophan derivative

Answer 9

T3

Question 10

features of tyrosine/tryptophan derivatives

Answer 10

enzymatic pathways regulate production
stored in vesicles
Ca2+ influx releases vesicles
amines are hydrophilic and transported free in plasma

Question 11

why do steroids and thyroxine need carrier proteins

Answer 11

insoluble in plasma

Question 12

why do proteins and peptides not need carrier proteins

Answer 12

soluble in plasma

Question 13

name three specific carrier proteins

Answer 13

cortisol binding protein
thyroxine binding globulin (binds T3/4)
sex steroid binding globulin (binds testosterone and oestradiol)

Question 14

name two general carrier proteins

Answer 14

albumin - bind many steroids and thyroxine

transthyretin - binds thyroxine and some steroids

Question 15

how are hormone levels controlled

Answer 15

negative feedback

Question 16

three types of hormone receptor

Answer 16

GPCR
Tyrosine kinases
nuclear receptors

Question 17

features of GPCR

Answer 17

largely activated by proteins/peptides/amines

signalling occurs via cAMP cascades or IP3, PKC pathway

Question 18

features of tyrosine kinases

Answer 18

these can be intrinsic (insulin) or have associated activity (phosphorylate proteins to mediate signal transduction)

Question 19

features of class 1 nuclear receptors

Answer 19

activated by many steroids
stay in cytoplasm
translocated to nucleus when activated

Question 20

features of class 2 nuclear receptors

Answer 20

activated mostly by lipids
stored in nucleus
ligand must diffuse through membrane to reach receptor