Hormone Synthesis And Action Flashcards
What are the two types of hormones (in terms of synthesis and action) ?
Peptides and proteins
steroids and iodinated tyrosines
How are proteins/ peptide hormones synthesised?
Transcription
What are the parts of pre-prohormones?
Signal + hormone + peptide sequences
What are the parts of the prohormone?
Hormone + peptide sequences
What parts of the endocrine system are controlled by the hypothalmic- pituitary axis?
Thyroid, adrenal cortex and gonads
What does stAR stand for?
Steroidogenic acute regulatory protein
What is scc?
Cytochrome C
What is T3 made up of?
One monoiodinated tyrosine and one diiodinated tyrosine
What is T4 made up of?
Two diiodinated tyrosines
What is the general action of peptide and protein hormones?
Activate second messengers and/ or enzymes
What is a G protein coupled receptor made up of?
7 transmembrane binding domains, one extracellular binding domain (N terminus)
One intracellular domain (C terminus)
What are receptor tyrosine kinases made up of?
One transmembrane domain
one extracellular binding domain (N terminus)
One intracellular binding domain bound to a tyrosine kinase domain
What are the names of the two types of signalling pathway related to GPCRs?
Adenyl cyclase and cAMP signalling pathway
Phosphoinositide signalling pathway
What are the names of the two types of signalling pathway related to tyrosine kinase receptors?
Raf/MEK/ERK1/2 pathway
PI3 kinase/AKT signalling pathway
What are steroid hormone receptors?
A family of transcription factors
What are the different functional regions of the receptor called?
Domains A-F
What is the function of the c domain?
DNA binding region
What do both the A/B and E/F domains do?
Transcriptional activity
What does the E domain do?
Ligand binding domain
What does C domain contain and how does it help its function?
Zinc fingers that allow part of the transcription factor to bind to DNA
What are the two possible causes of insufficient insulin?
Type 1 and type 2 diabetes
What happens in type 1 diabetes?
Autoimmune destruction of pancreatic islets -> absolute insulin deficiency
What happens in type 2 diabetes?
Insulin resistance, partial loss of insulin production (insulinopaenia)
What does insulin resistance lead to?
Hyperglycaemia, dyslipadaemia, hypertension, endothelial dysfunction, inflammation and impaired thrombolysis
What happens if there’s an aromatase deficiency in men?
Can’t synthesise oestrogens from androgens -> no epiphyseal closure -> long stature and elongated bones
What happens if there’s an aromatase deficiency in women?
Virilisation of XX foetuses
Cliteromegaly
Ambiguous genetalia
What does an enlargement of the thyroid gland cause?
Lack of iodine in the diet -> T3/4 deficiency
Graves’ disease
Thyroid adenoma
What is Graves’ disease?
Hyperthyroidism
What happens in Graves’ disease?
Autoantibodies in the TSH receptor act on the thyroid gland to stimulate excess thyroid hormone
