Endo 2

Question 1

What are the three major classes of hormones?

Answer 1

Amines (half-life: 2-3 mins)

Peptides/Proteins (half-life: 4-170 mins)

Steroids (half-life: minutes to several hours)

Question 2

What are the types of amines?

Answer 2

Catecholamines and indolamines

Question 3

How are catecholamines and indolamines are similar?

Answer 3

They have short half-lives (2-3 mins), they act very fast and are rapidly degraded
They travel freely in the blood
Always bind to a membrane receptor to activate second messenger signaling pathways

Question 4

What are the main differences between catecholamines and indolamines?

Answer 4

Catecholamines are synthesized from a single tyrosine and its rate limiting enzyme is tyrosine hydroxylase
Indolamines are synthesized from a single tryptophan and its rate limiting enzyme is tryptophan hydroxylase

Question 5

What are the catecholamines?

Answer 5

dopamine, NE, and Epi

Question 6

How do we get dopamine?

Answer 6

Tyrosin —> L-DOPA by tyrosine hydroxylase

L-DOPA —> Dopamine by amino acid decarboxylase