Exam 2- Lecture 11 Flashcards
juxtacrine signaling is _____ physical contact
direct
true or false: endocrine signaling travels fairly far through the blood to a target organ
true
is endocrine signaling low or high in concentration?
low
is endocrine signaling a high or low affinity receptor?
high
time frame for endocrine signaling
minutes to hours
paracrine signaling travels a _____ distance and affects neighboring cells
a. short
b. long
a. short
does paracrine signaling have a high or low local concentration?
high
does synaptic signaling travel a short or far distance?
short (very)
3 sex and progestational hormones to know and how many carbons?
progesterone (C21)
17β-estradiol (C18)
testosterone (C19)
2 adrenocortical hormones to know and how many carbons?
cortisol (C21)
aldosterone (C21)
cortisol is a glucocorticoid with what two functions?
anti-stress hormone, inflammation
aldosterone is a mineralocorticoid with what two functions?
regulator of Na+ uptake in the kidney
raises blood volume and bp
where are sex hormones made?
ovaries and testes
when aldosterone levels are high, we have _____ sodium reuptake
a. more
b. less
a. more
are steroid receptors extracellular or intracellular?
intracellular
steroid receptors contain what two domains?
DNA-binding domain
hormone-binding domain
when a DNA-binding domain binds to a hormone responsive element (HRE), what happens?
binding alters the rate of transcription
CRH is released from where?
hypothalamus
CRH stimulates release of ACTH from the (anterior/posterior) pituitary gland
anterior
what is the target organ for ACTH?
adrenal gland
ACTH acts on what hormone?
cortisol
where is cortisol produced?
adrenal glands
the first step of steroid synthesis is cholesterol to pregnenolone and is catalyzed by what enzyme?
p450scc (CYP11A1)
cause of 17α-hydroxylase deficiency
mutations in CYP17A1, which has both 17α-hydroxylase and 17,20-lyase activities
what enzyme deficiency is an overproduction of mineralocorticoids and deficiency of corticosteroids and sex hormones?
17α-hydroxylase deficiency
3 symptoms of 17α-hydroxylase deficiency
-hypocortisolism -> enlargement of adrenal glands
-ambiguous genitalia
-hyperaldosteronism -> hypertension
what is the minor form of congenital adrenal hyperplasia? (5%)
17α-hydroxylase deficiency
what is the major form of congenital adrenal hyperplasia? (95 %)
21-hydroxylase deficiency
cause of 21-hydroxylase deficiency
mutation in CYP21A2, which functions as 21-hydroxylase
5 symptoms of 21-hydroxylase deficiency (slide 20)
-hypocortisolism -> adrenal gland enlargement
-hypoaldosteronism -> hyponatremia
premature androgen exposure:
-ambiguous genitalia in females
-hirsutism
-early epiphyseal closure -> short stature
what enzyme converts testosterone to 17β-estradiol?
aromatase
2 plasma transport proteins for steroids
-corticoid-binding globulin (transcortin) -> glucocorticoids and progesterone
-sex hormone binding globulin (SHBG) -> testosterone and estradiol
where are steroids metabolized?
liver
where are steroids excreted? (2 of them)
-bile (estrogen)
-urine (progesterone, androgens, and glucocorticoids)
aminoglutethimide brand name
Cytadren
aminoglutethimide (Cytadren) is used to block steroid production in some hormone-dependent tumors (breast, prostate) and works by inhibiting what two enzymes?
aromatase, P450scc
ketoconazole blocks the synthesis of __________ in fungi
ergosterol
ketoconazole inhibits what 3 enzymes?
P450scc, 17α-hydroxylase, 11β-hydroxylase
ketoconazole can treat hyperglucocorticoid stress, also known as what syndrome?
Cushing’s syndrome
