L04: Hormone synthesis and action Flashcards
What are the 3 main hormones
- protein
- steroid
- amines
Give an example of a protein hormone
Insulin
Give an example of an steroid hormone
Cortisol
Give an example of an amine hormone
T4, T3
How are protein hormones synthesised
- Pre-mRNA is translated in the RER as a pre-prohormone
- pre-prohormone > prohormone > hormone by proteolysis enzymes
- protein can be modified in the Golgi by glycosylation
If a Golgi apparatus modifies a protein by glycosylation what hormone would be produced
A glycoprotein which is a protein with carbohydrate attached to it
How do glycoproteins of anterior pituitary hormones vary
They have the same alpha subunit but different beta subunit which makes the specific
How are steroid hormones synthesised
- cholesterol from the hydrolysis of esters is transported to the mitochondria by STAR transporter
- mitochondria produced pregnelone
- pregnelone is processed in the smooth endoplasmic reticulum (SER) which gives the specific hormone
Which gland are steroid hormone mostly produced in
The adrenal gland
What are the three layers of the adrenal cortex
- zona glomerulosa
- zona fasciculata
- zona reticularis
What type of hormone does the zona glomerulosa synthesis
Mineralocorticoid
What type of hormone does the zona fasciculata synthesis
Glucocorticoid
What type of hormone does the zona reticularis synthesis
Adrenal androgens
What type of hormone does the adrenal medulla synthesis
Catecholamines
Are steroid hormones stored or secreted straight after synthesis
They are not stored and secreted rapidly after synthesis
How are amine hormones synthesised
- TSH binds to TSH receptors on the follicular membrane
- iodine is brought into follicular cells by iodine/sodium transporter
- iodine binds to thyroglobulin (stored in the calloid) by thyroperoxidase enzyme
- MIT and DIT form
- MIT+DIT=T3 and DIR+DIT=T4
- exocytosis occurs
What type of receptors does proteins binds to
Cell surface receptors
What type of receptors does steroid bind to
Intracellular receptors
Are proteins hydrophobic or hydrophilic
Hydrophilic
Are steroid hydrophobic or hydrophilic
Hydrophobic
What are thyroid hormones transported with in the blood
- albumin
- TBG
- transthyretin
