Endocrinology 2 Flashcards
What are the three classifications of hormones depending on the structure?
- Proteins
- Lipids
- Monoamines
What are the three subtypes of Protein hormones?
- Small Peptides
- Polypeptides
- Glycoproteins
What are Glycoproteins?
Proteins combined with a sugar
What are the small peptides?
- TRH
- Oxytocin
- ADH
What are the two subtypes of Lipid hormones?
- Steroids
* Eicosanoids
What are steroid made from?
Cholesterol
What are Eicosanoid made from?
Arachidonic acid
Where are protein hormones soluble and insoluble?
They are soluble in an aqueous environment and insoluble in a fatty environment
What are the two subtypes of Monamines?
- Catecholamines
* Thyroid stimulating hormones
Where are steroid hormones relatively soluable?
In a fatty/lipid environment
What are Catecholamines made of?
Tyrosine
What are thyroid hormones made of?
Tyrosine
How are steroid hormones produced?
- They start as cholesterol and is converted to Pregnenolone
* Pregnenolone is converted to progesterone which than can be converted to many things
What three things can Progesterone be converted into?
- Testosterone
- Aldosterone
- Cortisol
What can Testosterone be converted into?
Estrogen
What two things can be converted to testosterone?
Pregnenolone and Progesterone
What is Paracrine communication?
A hormone-producing cell targets nearby neighbouring cells, so the hormone stays nearby and diffuses through extracellular fluid
What is autocrine communication?
A hormone-producing cell releases hormones and the hormones act on the cell that produced them. Or they do not even leave the cell and act on receptors within the cell (intercrine)
How does neuroendocrine communication work?
The nerve and endocrine portion work together. The hormones are produced within the nerve cell body and are transported down the axon and are stored in the nerve terminal. Stimulation causes the release of the stored hormone which goes into the blood so that it can arrive at its target cell
How do hormones interact with their targets?
The hormone or ligand binds to a receptor which interacts with other molecules leading to a response in the target cell
What are the two classifications of hormone receptors?
- Cell surface receptors
2. Intracellular receptors
What are cell surface receptors?
Proteins which bind to protein hormones and to catecholamine
What are Intracellular receptors?
Proteins which bind to steroid hormones and to thyroid hormones, T3 and T4
What are the two types of Cell surface receptors?
- G-protein linked receptors
* Catalytic receptors
What do G-proteins regulate?
Intracellular second messengers (cAMP, DAG, Ca2+)
What are Catalytic receptors?
Receptors that either have enzyme activity (tyrosine kinase) or are closely associated with an enzyme after binding to a ligand
Which kinds of hormones bind to catalytic receptors?
Insulin and growth hormone
