endocrinology- basic principles :0 Flashcards
examples of protein and polypeptide hormones
- growth hormones
- prolactin
- insulin
- oxytocin
these are hormones encoded by genes made up of amino acid chains of various lengths
examples of amino acid derived hormones?
- tyrosine
- adrenaline
- tryptophan
- melatonin
much smaller hormones
examples of steroid hormones?
- cholesterol
- testosterone
- oestradiol
where are steroid hormones usually synthesised?
- adrenal glands
- reproductive organs
what are the 4 main groups of hormone receptors?
- G protein coupled receptors
- Receptor Tyrosine Kinase (RTK) Families
- Receptors associated with tyrosine kinase activity
- Steroid hormone receptors
what similar features do all G-protein couples receptors share?
all have:
- an extracellular domain
- an intracellular domain
- 7 transmembrane domain
what does the extracellular domain in G protein coupled receptors do?
ligand binding
what does the intracellular domain in a G couples protein receptor do?
activates intracellular signalling cascade
what type of receptor is the insulin receptor?
receptor tyrosine kinase families
where are steroid hormones receptors usually found?
-intracellular either in cytoplasm or nucleus
what will the ability to accurately measure hormone levels depend on?
-pattern of secretion
-the presence of carrier hormones
-interfering agents
-stability of hormones
-absolute concentration
!!major determinant= rate of secretion!!
what would a raised TSH suggest?
hypothyroid
what would a suppressed TSH suggest?
hyperthyroid
why might it not be reliable to measure TSH levels in unwell patient?
their TSH levels may fall and then rise later on
would taking a random cortisol test be a good indication of HPA axis function?
no, cortisol varies so much throughout the day, it would be better to take it at 9am
-need dynamic testing to really tell HPA axis function
