Principles of Endocrinology Flashcards
Why are petide hormones injected?
Digested if ingested
Which hormone type is being described below?
- Synthesized as prehormones
- Stored in membrane-bound secretory vescicles
- Regulated at the level of secretion and synthesis
- Often circulate in blood unbound
- Usually administered by injection
- Signal through transmembrane receptors
Peptide
NOTE: Stimulus for their release probably comes from another hormone/ substrate/ mineral and they are released by exoxcytosis because they are in vesicles.
Which hormones use the cAMP secondary messanger?
- Epinephrine and norepinephrine
- Glucagon
- Luteinizing hormone
- Follicle stimulating hormone
- Thyroid-stimulating hormone
- Calcitonin
- Parathyroid hormone
- Antidiuretic hormone
Which hormones use the protein kinase secondary messanger?
- Insulin,
- Growth hormone
- Prolactin
- Oxytocin
- Erythropoietin
- Several growth factors
NOTE: GH and prolactin don’t use an auto tyrosine kinase method. They must be activated
Which hormones use calcium and/or phosphoinositides as a second messenger?
- Epinephrine and norepinephrine
- Angiotensin II
- Antidiuretic hormone
- Gonadotropin-releasing hormone
- Thyroid-releasing hormone.
Which hormones use the cGMP second messenger?
- Atrial naturetic hormone
- Nitric oxide
List steroid hormones and the site of synthesis.
-
Cortisol
- Adrenal cortex
-
Aldosterone
- Adrenal cortex
-
Androgens
- Adrenal cortex
-
Testosterone
- Testes
-
Estrogens, Progesterone
- Ovaries
- Corpus Luteum
- Placenta
-
1,25-Dihydroxycholecalciferol
- Kidneys
Precursor for steroid hormones
Cholesterol
Process by which progesterone and cortisol are synthesized
- LDL is endocytosed into the cytoplasm as a cholesterol ester
- Cholesterol esters then join with acetyl CoA to form cholesterol
- Cholesterol enters the mitochondria
- Cholesterol is converted to pregnenolone via the side chain cleavage enzyme
5.Pregnenolone then enters the SER where it is converted to progesterone
- Progeseterone is then convereted to 17-OH- Progesterone
- 17-OH-Progesterone is then converted to 11- Deoxycortisol
- 11-Deoxycortisol is converted to cortisol
Which hormone type is being described below?
- Derived from enzymatic modification of cholesterol
- Cannot be stored in secretory vesicles becuase of lipophilic nature
- Regulated at the level of the enzymatic pathway required for their synthesis
- Transported in the blood bound to transport proteins
- Signal through intracellular receptors
- Can be administered orally
Steroid
Steroid hormones have sections of DNA called ______________.
Hormone response elements
NOTE: When they bind to regions of DNA they will stimulate or repress transcription of a particular gene
List amine hormones and their site of synthesis.
-
Dopamine
- Hypothalamus
-
T3, T4
- Thyroid
-
NE, EPI
- Adrenal medulla
-
Melatonin
- Pineal gland
NOTE: All of the above are made from tyrosine, with the exception of melatonin, which is made from tryptophan
Mechanism of synthesis of norepinephine/epinephrine.
- Tyrosine is converted to L-Dopa via tyrosine hydroxylase
2. L-Dopa is convered to dopamine bia dopa decarboxylase
3. Dopamine is converted to norepinephrine via dopamine B- hydroxylase
4. Norepinephrine is converted to epinephrine via phenylethanolamine N- methyltransferase
NOTE: Norepinephrine is primarily found in nerve terminals of sympathetic system. Epinephrine is primary found in the adrenal medulla
Which hormone stimulates phenylethanolamine-N-methyltransferase?
Which hormone type is being described below?
- Derived from the iodination of thyronines
- Lipophilic, but stored in thyroid follicle by covalent attachment to thyroglobulin
- Regulated at the level of synthesis, iodination, and secretion
- Transported in blood tightly bound to proteins
- Signal through intracellular receptors
- Can be administered orally
Thyroid hormones