3-Peptide and steroid hormones Flashcards
Which type of hormones are GPCR ligands
Polypeptides/ modified amino acids
Which hormones are derivatives of tyrosine
Tyrosine > dopamine > noradrenaline > adrenaline
Which hormones are derivatives of tryptophan
Tryptophan > serotonin > melatonin
Why do we still express some genes we don’t need
GPCR ligands can be too efficient and if the environment changes, you may have been too specific for the last environment
The genes that are expressed were once useful to ancestors but if they aren’t used in a very long time they will eventually mutate away
Receptor tyrosine kinase ligands mechanism
E.g., Insulin
Dimerise when ligand binds and trans phosphorylate each other
Examples of steroid hormones
Cortisol, aldosterone and the sex hormones
Peptide hormone synthesis
Syntheisised in the golgi or the RER and stored in vesicles
Fuse with membrane by snap SNARE complexes
How is peptide hormone release controlled
Regulated by cAMP or high cytosolic Ca2+
G proteins
What do the individual G proteins do
GDP exchanged for GTP
Gs activates adenylate cyclase
Gi inhibits adenylate cyclase
Gq modify calcium levels
interacts with phospholipase 3 and the smooth ER has calcium ATPases
Where are steroid hormones released from
Adrenals, gonads and placenta
What do all steroid hormones stem from
Cholesterol
Mechanism of steroid hormones
Bind cytosolic receptors, have longer lasting and more profound effects
