Endocrinology basic principles

Question 1

major endocrine glands

Answer 1

hypothalamus 
pituitary 
parathyroids 
thyroid 
adrenals 
pancreas 
ovaries 
testes

Question 2

types of hormones

Answer 2

proteins
peptides
steroids
modified amino acids

Question 3

types of hormone receptors

Answer 3

g-protein coupled
receptor tyrosine kinase
nuclear receptor
hybrid

Question 4

what is a tyrosine kinase receptor

Answer 4

tyrosine residue becomes phosphorylated resulting in intra cellular signalling

Question 5

where are nuclear receptors found

Answer 5

mainly in the nucleus as they require active uptake of the hormone into the cell

binding of hormone to the receptor stimulates change in gene transcription

slow acting

Question 6

what are g-protein coupled receptors

Answer 6

receptors that are coupled to g-proteins lol

have an extracellular domain (ligand binding domain) then has a 7 transmembrane domain

associated with G proteins (alpha, beta, gamma)

G-proteins stimulate intracellular messengers eg, cyclic AMP

Question 7

what are receptor tyrosine kinase receptors

Answer 7

insulin receptor

preformed dimer

Question 8

what are cytokine receptors (linked to tyrosine kinase activity)

Answer 8

preformed dimers at cell surface
when a ligand binds there is phosphorylation
leads to conformational change in receptor
allows signalling to pass through??

Question 9

how do steroid hormone receptors work

Answer 9

nuclear receptors found in cytoplasm or nuclear

binds to DNA and results in changes in transcription

Question 10

what is the hypothalamic pituitary axis

Answer 10

signals come into hypothalamus resulting in release of hormones which target anterior pituitary signalling pituitary hormone release

Question 11

what does the posterior pituitary secret

Answer 11

ADH

Oxytocin

Question 12

what does the anterior pituitary secrete

Answer 12

GH
SCTH
TSH
PRL

Question 13

what to think about when measuring hormones

Answer 13

what time to check it to get most reliable reading

Question 14

what hormones are commonly measured

Answer 14

thyroid 
steroid hormone 
growth hormone 
reproductive and sex hormone 
prolactin 
calcium and parathyroid hormone

Question 15

when might TSH not be a reliable marker of thyroid stats

Answer 15

in pituitary dysfunction (secondary hypothyroidism)

Question 16

when shouldn’t you measure thyroid hormone

Answer 16

when patients is sick in hospital

will usually level out when they get better

Question 17

how do you asses pituitary gland function

Answer 17

check 
9am cortisol 
FT4, FT3, TSH
Prolactin 
IGF1 
LH, FSH, E2, Testosterone 
U&Es, plasma/urine osmolarity 

MRI
synacthen test?? give synthetic ACTH and asses cortisol response, check adrenal glands aren’t dormant due to lack of stimulation from pituitary gland

Question 18

what time should you measure cortisol levels

Answer 18

9am - just after morning peak
if you measure it randomly it could be v low due to normal circadian rhythms

measure at 9am to check its there and check between 9pm and 12am to check that it goes away appropriately

Question 19

what is measured instead of growth hormone to show growth hormone status

Answer 19

IGF-1 shows levels of growth hormone secretion

GH hard to measure bc it fluctuates during the day

Question 20

what time to measure testosterone

Answer 20

9am