Where are catecholamines made? - Answers Made by the adrenal medulla and by sympathetic and
parasympathetic nervous system?
What is the rate limiting step in the synthesis of catecholamines? - Answers Tyrosine hydroxylase
What increases the synthesis of DBH in the adrenal medulla? - Answers Glucocorticoids from the adrenal
cortex
What converts norepinephrine to epinephrine? - Answers Phenylethanolamine-N-methyltransferase
Where is epinephrine made? - Answers The adrenal medulla
What degrades epinephrine? - Answers Catechol-O-methyltransferase (COMT) and monoamine oxidase
(deaminates the catecholamine)
How does monoamine oxidase degrade epinephrine? - Answers Deaminates that catecholamine
What are pheochromocytomas? - Answers Tumors of the adrenal medulla that overproduce
epinephrine and norepinephrine
What are eicosanoids made of? - Answers Made from arachidonic acid, a fatty acid with 20 carbons
(eikosi = 20 in Greek) and four double bonds (20:4).
What is the effect that prostaglandin synthase has on arachidonic acid? - Answers Converts it into
prostaglandin H2.
Arachidonic acid is converted into prostaglandin H2 by what? - Answers Prostaglandin synthase
The two components of prostaglandin synthase are... - Answers Cyclooxygenase and a hydroperoxidase
What is prostaglandin H2 (PGH2) a precursor to? - Answers Prostacyclin, Thromboxanes, Prostaglandins
What does aspirin inhibit? - Answers Cyclooxygenase irreversibly, due to acetylation of specific serine in
the enzyme.
Why is aspirin considred antithrombotic? - Answers It inhibits formation of PGH2, the precursor of
thromboxane A2, a potent aggregator of blood platelets.
What is a catechol? - Answers A benzene with two hydroxyl side groups.
What are some examples of a catechol? - Answers Dopamine, epinephrine, norepinephrine
What enzyme degrades epinephrine via the deamination of the catecholamine? - Answers Cetechol-O-
methyltransferase
, What are the five classes of steroid hormones? - Answers Androgens, Estrogens, Glucocorticoids,
Mineralcorticoids, and Progestins
What is the structural identifier for steroid hormones? - Answers Three 6-member carbon rings, one 5-
member carbon ring.
Is vitamin D a steroid? - Answers No, it is considered a lysosteroid, not classified functionally as a steroid.
What is an example of an androgen? - Answers Testosterone and dihydrotestosterone
What is an example of an estrogen? - Answers 17ß-estradiol, estrone, and estriol
What is an example of a glucocorticoid? - Answers Cortisol and corticosterone
What is an example of a mineralocorticoid? - Answers Aldosterone and deoxycorticosterone
What is an example of a progestin? - Answers Progesterone
What is the cause of the specificity of steroid hormones? - Answers The position of hydroxy groups on
the ring structure
How do cells compensate for steroids insolubility in serum? - Answers They bind to carrier proteins, as a
result they have relatively long half lives
Steroid half lives are... - Answers Generally long, due to the binding of the steroid to a carrier protein.
Where do steroids bind? - Answers Bind to either cytoplasmic or nuclear intracellular receptors to
modulate transcription.
What is an example of a thyroid hormone? - Answers Thyroxine (T4) and Triiodothyronine (T3)
What is an example amino acid derivative? - Answers Histamine, epinephrine
What is an example of eicosanoids? - Answers Prostaglandins and thromboxanes
What are some examples of isoprene derivatives? - Answers Steroid, Vitamin D, Retinoids
Describe eicosanoids - Answers Lipid soluble hormones that bind to membrane receptors that are
usually G-protein coupled. They have paracrine and possibly autocrine effects.
What receptors do eicosanoids usually bind to? - Answers G-protein coupled receptors
What is Cycloxygenase (COX)? - Answers An enzyme that is responsible for formation of prostaglandins
and thromboxane.
What is retinoic acid derived from? - Answers ß-carotene
What does all-trans retinoic acid do? - Answers It is a hormone involved in differentiation, binds to a
nuclear receptor, retinoic acid receptor (RAR).