Lecture 4+5 Flashcards
conversion of cholesterol to pregnenolone?
that is done by the enzyme P450scc or also known as CYP11A
what kinds of hormones are synthesized in the adrenals? examples?
Glucocorticoids: Cortisol
Mineralocorticoids: Aldosterone
Weak Androgens:
Dehydroepi-androsterone (DHEA)
Androstenedione (ADD)
types of hormones produced in the gonads and corpus luteum? examples?
male gonad: androgens (testosterone)
female gonad: estrogens (Estradiol)
corpus luteum: progestins (progesterone)
aldosterone synthesis and regulation?
cholesterol… pregnenolone….. progesterone
11-deoxycorticosterone….. corticosterone is converted to aldosterone by aldosterone synthase or CYP11B2
angiotension II leads to the synthases of that enzyme
where is cortical synthesized?
how is it regulated?
produced in the zona fasciculata
ACTH activates protein kinase A
Protein kinase A activates cholesteryl esterase
StAR moves the cholesterol into the mito (regulated step)
P450scc is regulated by cholesterol availability
androgen synthesis? how many carbons?
what happens when they go into the blood?
Androgens have 19 Carbons and are mainly produced in the zona reticularis
If in adipose tissue DHEA and androstenedione are converted to estrogens by CYP 19 aromatase
If in extra-adrenal tissue they are converted to testosterone by 17 beta hydroxysteroid DH-3
what are the different types of congenital adrenal hyperplasia’s?
- 3 hydroxysteroid DH deficiency
- 17 alpha hydroxylase deficiency
- 21 alpha hydroxylase deficiency
- 11 beta hydroxylase deficiency
3 hydroxysteroid DH deficiency
effects?
what is impacted?
blood pressure - low blood glucose - low androgens - variable (high DHEA) salt excretion in urine ambiguous genitalia in both sexes
less aldosterone and less cortisol due to low progesterone
less androstenedione
CYP 17 or 17 alpha hydroxylase deficiency
effects?
impact?
hypertension
low blood glucose
decreased androgens
female like genitalia in both sexes
Low cortisol, low DHEA, low ADD, low aldosterone
But high aldosterone intermediates
CYP 21 or 21 alpha hydroxylase deficiency
hypotension often low blood glucose increased androgens hyponatremia hyperkalemia
low aldosterone and low cortisol
high DHEA and ADD
male seem normal, but virilization early
female have male-like and virilization later
CYP11B1 or 11 beta hydroxylase deficiency?
mild hypertension
low glucose
increase androgens
low cortisol and low aldosterone
sex hormone synthesis in male gonads?
hypothalamus releases GnRH to anterior pituitary
anterior pituitary releases LH and FSH
LH to leydig cells for testosterone production
FSH to steroli cells for spermatogenesis
Formation of testosterone and dihydrotestosterone?
leydig cells have CYP 17 which converts ADD to testosterone
testosterone is activated into dihydrotestosterone by 5-alpha reductase in prostate and hair follicles
DHT has a higher affinity for the androgen receptor
sex hormone synthesis in female gonads?
hypothalamus releases GnRH
goes to pituitary and releases LH and FSH
LH goes to theca cells to produce testosterone
FSH goes to follicle granulosa cells to produce estradiol (take up testosterone to produce estradiol)
conversion of testosterone into estradiol?
aromatase does that conversion (CYP 19)
