Steroids Flashcards
What is the precursor molecule for steroid hormones?
cholesterol
Where does the body get cholesterol from?
the diet and from synthesis in the liver from acetyl CoA
What is the enzyme required for cholesterol synthesis?
HMG-CoA reductase
Where does the last stage of cholesterol synthesis occur?
in the endoplasmic reticulum
What enzyme is required to convert male sex steroids to female sex steroids?
aromatase
What are the two types of corticosteroids?
mineralocorticoids (aldosterone) and glucocorticoids (cortisol)
How are steroid hormones metabolised?
by CYP3A4 in the liver to form bile acids
How are sex steroids transported in the blood?
on sex steroid binding protein
Where is the receptor for sex steroids?
in the cell nucleus
Where is the receptor for adrenal steroids (glucocorticoids and mineralocorticoids)?
in the cell cytosol
Where does the activated steroid receptor bind?
to the hormone response element on DNA
What is cyproterone acetate and what is it used for?
an inhibitor of the nuclear androgen receptor - used to treat hirsuitism, male to female gender changes, prostate cancer, priapism and hypersexuality
What hormones in the hypothalamus and anterior pituitary lead to the release of adrenal steroids?
CRH and ACTH
What hormones in the hypothalamus and the anterior pituitary lead to the relase of sex steroids from the gonads?
GnRH and FSH/LH
What is the function of mineralocorticoids?
promote retention of sodium and water to increase blood pressure and blood volume