quiz 2 sex hormones Flashcards
androgens
hormones usually associated with men and maleness
where are androgens also found
in women, but 8x less common
where are androgens synthesized
in the adrenal glands in both sexes, ovaries of females and testes of males
most common and most important androgen
testosterone
all androgens are born out of what molecule
cholesterol
all androgens are
steroids
all androgens
need something to guide them through blood since not water soluble
what does testosterone bind t in blood
sex hormone binding globulin so it can travel through blood
when to androgens need to be released
at the onset of puberty
what happens so androgens can be released
the hypothalamus begins to create and secrete the protein GnRH
GnRH
gonadotropin-releasing hormone
GnRH does what
leaves the hypothalamus and travels to the pituitary gland
what does GnRH do at the pituitary gland
where it causes the secretion of a second protein hormone called LH
LH
luteinizing hormone
LH does what
leaves the pituitary gland and finds luteinizing hormone receptors
where are luteinizing hormone receptors located
in Leydig cells in the testes
Leydig cells begin what
the synthesis of testosterone
what is the HPG axis
the hypothalamus, pituitary, gonad
the HPG axis is the pathway the body uses….
to control sex hormone production
testosterone will enter cells and find…
androgen receptors
androgen receptors interact
with DNA to upregulate or downregulate at least 84 different genes (leads to many effects)
wat does testosterone do in vitro
- high enough levels lead to formation of the penis and gonads
- leads to masculinization or feminization of the brain even more than levels once the fetus reaches adulthood
wat does testosterone do in puberty
- leads to an increase in muscle mass
- leads to an increase in bone mineral density
- leads to formation of body hair, acne
wat does testosterone do in adults
- leads to the formation of sperm in males
- leads to increased sex drive (both sexes)
- romance, fatherhood leads to decreased testosterone levels
anabolic steroids
injecting or ingesting chemicals that are testosterone or are very chemically similar. banned in most sports
farquharson phenomenon
body adjusts to new levels of androgens and stops producing its own. once doping stops, body produces far too little testosterone
castrati
male singers who were castrated before onset of puberty
what happens to castrati
voices never dropped, so they could sing very high ranges.
what else happens to castrati
their epiphyseal plates never hardened, so their bones (ribs) grew longer
low T
testosterone levels begin to drop slowly after the age of 30, in some more than others
what is normal range of testosterone
300-1000 ng/dl
extreme case of low t are called
andropause or male menopause
what happen be given to treat low T
testosterone supplements through the skin or in a transplant
is a estrogen a hormone
no its a class of hormones (like androgen)
what are the three most important estrogens
estradiol, estrone, estriol
estradiol
most common estrogen during reproductive years (menarche to menopause)
estrone
most common estrogen after menopause
estriol
most common estrogen during pregnancy
estrogens are primarily
found in women, but are also in men at lower rates
potency of estradiol
100%
potency of estrone
33%
potency of estriol
1.6%
estradiol levels…
vary widely through the menstrual cycle
estrogens all
come from cholesterol
estrogens can all
enter cells but are not water soluble
what does estrogen also bind to in blood
sex hormone binding globulin (same as androgens)
testosterone can be broken
down into estrogens
estrogens follow a similar
release pattern to androgens
what is the release pattern of estrogens ( first step )
GnRH is made, which causes LH to be made
in females where does LH bind to
receptors on granulosa cells in the ovaries which causes estrogens (estradiol) to be synthesized and secreted
the estrogen pathway happens in
HPG AXIS
estrogens bind to a variety of
estrogen receptors
what can estrogen binding to estrogen receptors do
- formation of breast
- slowed height increase in puberty
- slowed bone resorption less osteoclast activity: RANK pathway)
- regulation of the mentrual cycle (along w/ other hormones)
what is estrogen necessary for in men
the production of sperm
what are contraceptives
pills with synthetic estrogens that mimic estradiol and cause irregular estrogen levels
breast cancer..what does estrogen do
most cases are E-R positive, meaning that the presence of estrogen causes the cancer to grow faster
gynecomastia (what does estrogen do)
the formation of mall breasts in men.
when does gynecomastia happen
common (70%) in puberty and in later life
other non-estrogen hormones that are crucial to women’s reproduction
LH, FSH, progesterone
what does LH do in women
stimulates granulosa cells to produce estrogens, required for ovulation to occur
FSH
follicle-stimulating hormone
FSH function
another protein hormone that is also essential for ovulation
what is progesterone
a steroid released late in the mesntrual cycle
what does progesterone do
causes mucus levels to thicken in the uterus and allow for a potential zygote to stick
what does progesterone inhibit
the production of GnRH, meaning that LH and estradiol levels will decrease
progesterone is
a precursor to the estrogens (and androgens)
the journey from cholesterol to sex hormones
cholesterol, progestagens, androgens, estrogens
the female reproductive hormones work to regulate each other
in negative or positive feedback loops
levels of estradiol, FSH, progesterone
…vary across the menstrual cycle
how to contraceptives work
trick the body into thinking progesterone levels are high (and sometimes alter levels of estrogens to)
what would the presumed high levels of progesterone do w/ contraceptives
stop GnRH from being produced, which stops both LH and estradiol from being made
endocrine is the opposite of the
nervous system
endocrine and nervous system both
transmit signals around the body
the nervous system is built on
speed
the endocrine system is ____ and always uses
slower, hormones
there are about _____ distinct hormones in the human body
50
what are the three classes of hormones
amino acid derivatives
proteins
steroids
depending on the type the _____ of a hormone can be different
mechanism
what is a mechanism
how a chemical causes its desired effect
steroids are al synthesized from the molecule ____
cholesterol
steroids all look like
cholesterol
what do steroids usually end in
ol or one
what are hormones that are proteins
long chains of amino acids
hormones that are proteins are significantly
larger than other hormones and water-soluble
amino acid derivatives are synthesized from
various amino acids
what do amino acid derivatives look like
they are small and look like amino acids
what would amino acids (amino acid derivatives) look like
short chains of carbon
examples of amino acid derivatives
tyrosine, epinephrine
example of a protein that is a hormone
insulin
where are hormones created
in glands located around the body
where are hormones secreted
into the bloodstream, where they travel to their intended target target
steroids are not what? why ?
water-soluble, because they are made from cholesterol which is a lipids
what do steroids require to travel through blood
a transport protein
if amino acid derivatives are non polar they
need transport proteins
steroid hormones and most non polar amino acid derivatives are capable of what
passing through a cell’s membrane
once inside, steroid hormones and non polar amino acid derivatives do WHAT?
bind to receptors and form a hormone-receptor complex
what does the hormone receptor complex do
enters the nucleus and causes upregulation or downregulation of proteins
nonsteroid hormones and polar amino acid derivatives CANNOT..
pass through a cell’s membrane
to _____ nonsteroid hormones must
send signals to the cell, bind to a receptor on the cell’s membrane
a membrane receptor activated by a nonsteroid hormone
causes other molecules in the cell to invoke some kind of change
what are the most important hormones the thyroid produces
T4 and T3
T4
thyroxine
T3
triiodothyronine
T3 and T4 are jointly involved in
regulating cellular energy processes around the body
differences between T3 and T4
T4 has one more iodine
the thyroid is what percentage T4
80%
the thyroid is what percentage T3
20%
inside cells T4 is
converted to T3 (only one active in cells)
when are T3 and T4 made
when the pituitary gland secretes TSH
why do we even have T4
more stable in bloodstream
TSH
thyroid stimulating hormone
T4 and T3 are
derivatives of amino acid tyrosine, but have been combined with iodine
once secreted, what do T4 and T3 do
bind to the transport protein TBG and travel through blood
TBG
thyroxine-binding globulin
know thyroid gland
ok
goiter
an enlarged thyroid gland (developing countries)
what happens right after T3 and T4 enter the cell
T4 is converted to T3, T3 passes through the nuclear membrane and binds to TR
TR
thyroid hormone receptor
what happens without T3
the thyroid receptor binds to DNA and blocks certain genes from being expressed
the newly expressed genes because of T3 binding to Tr and moving it off DNA do…
increase the rate of cellular metabolism in cells all across the body
hyperthyroidism
when the thyroid makes too many hormones
hypothyroidism
is when the thyroid does not make enough hormones
PTH is made by
chief cells in the parathryoid glands
PTH is made in response to
low blood calcium leels (hypocalcemia)
PTH is a
protein
what does T3 do
bins and causes TR to move ff DNA, allowing those genes to be expressed
PTH binds to
parathyroid hormone receptors on the outer membranes of osteoblasts and osteoclasts
PTH causes
osteoblasts to slow down
osteoclasts to speed up
…. releasing more calcium from bone and into the blood
PTH is made of how many amino acids
84 (kinda small)
PTH also binds to….
receptors on the kindeys
PTH causes what on the kidneys
upregulation of an enzyme from a gene on DNA which converts calcidiol into Vitamin D
when is Vitamin D synthesized
when PTH sends a signal to the kidneys
vitamin D is also a what
hormone
what do people say is only partly true
that sunlight gives you Vitamin D
vitamin D is what kind of hormone
a steroid hormone since it is synthesized from cholesterol
what does sunlight directly cause
cholesterol to be converted into cholecalciferol in the skin
cholecalciferol…..
converted into calcidiol in the liver
calcidiol…
converted into vitamin D in the kidney
Vitamin D…..
attaches to vitamin d binding protein in the blood because it is not water soluble
once Vitamin D is in the blood
it travels until it finds and binds to a Vitamin D receptor
where are vitamin D receptors located
in the nucleus of small intestine cells
vitamin D and vitamin D receptor form
a hormone-receptor complex
what does the hormone-receptor complex of vitamin D and vitamin d receptor do
binds to DNA and causes increased expressions of protein calbindin
calbindin
a channel in the membrane of small intestine that allows calcium to enter and be digested
with more vitamin D
calcium levels increase
rickets
disease when there is a lack of vitamin D, phosphorus and calcium that results in soft, weak bones
myxedema
caused by the under-activity of thyroid gland during adulthood, causes weight gain
cretinism
under-secretion of T3 and T4 during infancy and fetal life
grave’s disease
hyposecretion of thyroid hormones, leads to weight loss
ghrelin
a protein hormone
what is ghrelin made by
cells in stomach and hypothalamus
what does ghrelin do
stimulate hunger and GH release
GH
growth hormone
what did they do for the ghrelin study
had 6 people fast, took their blood every 20 minutes
ghrelin study concluded
when your brain says its meal time ghrelin is released, (spikes in graph at meal time)
circadian tosis
you train yourself to eat at certain times of the day
BMI ghrelin
spikes at similar times but people with higher BMI had more ghrelin
