Flashcards in Hormones Deck (26):
Flutamide vs Faslodex?
Flutamide for male (Prostate), Faslodex for female (breast)
Peptide hormones stimulate what pathways (3 examples)
Lispro is the same as
Aspart is the same as
Insulin signaling pathway
TKr phosphorylates itself and IRS
SH2 domain-containing proteins bind to receptor
PI3 Kinase activated
PK-B is activated
Epinephrine signaling pathway
G Protein ----> PLC -----> PIP2 --------> DAG + IP3 (-->Ca++) ------->PKC
(PKC phosphorylates Glycogen Synthase (OFF) and Glycogen Phosphorylase (Activates "A")
Glucagon acts via what pathway
cAMP (mediates protein kinase that phosphorylates stuff)
Nonspecific = Albumin
Specific = Transcortin + SHBG
Only ____ steroid can enter cells
3 sources for Steroid Biosynthesis
-Cholesterol esters in cells
There are three pituitary hormones that play a role in regulating steroid biosynthesis. What are they and what do they do?
ACTH, LH, FSH
They activate production of:
Major regulator of Steroid biosynthesis. How is it (itself) regulated? What does it do?
CYP11A (Cholesterol Desmolase)
Activated by phosphorylation in mitochondria
Catalyzes C-C cleavage in a method other than hydrolysis
Cyp21-A2 reactions (2)
Progesterone to Deoxycorticosterone
Deoxycorticosterone to Cortisol*
in Zona Fasiculata
(in Zona Glomerulosa)
CAH cause and effect
21 hydroxylase (Cyp21-A2) deficiency
Causes decreased cortisol production -- more steroid shunted toward sex hormone synthesis
Aldosterone Synthase deficiency cause and effects. What does AS normally do (biochemically)?
Deficient in CYP11-B2, which is required for hydroxylation of deoxycorticosterone at C-11B and C-18
Steroid receptor domains (6)
-Transcription activation ( = variable & immunogenic)
-DNA binding ( = conserved)
-Transcription activation subdomain
DNA binding domain properties
Two Zn+-finger motifs. One binds DNA, one dimerizes
Cortisol suppresses inflammation via
Phospholipase A2 inhibition
Steps for ACTH stimulation of cortisol synthesis
cAMP--PKA--Cholesterol release from lipoprotein--StAR protein** -- Side Chain cleavage enzyme -- Pregnenolone
What is StAR protein?
StAR = Steroid Acute regulatory protein
Thyroid hormone synthesis pathway
TGlobulin--(Tyr's modified by iodine in colloid)--MIT/DIT ---T3/T4
What gets iodinated in Thyroid hormone synthesis? By what enzyme? Where?
Tyrosine residues, by Thyroid peroxidase, in the colloid
Plasma T3 & T4 exist in free form?
No, bound by Thyroxin BP