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9 hormones secreted from pituitary
need to know what part of pit.
What factors, conditions, hormones, stimulate
their release.
Need to know target tissues and induced responses
Need to know all feedback loops to pit and hyp.
Need to know cause, symptoms, and treatments of
all disease we cover in class
Test #2
__________
Mammary growth and Dev’t
Lactogenesis
__________ Roles in Vertebrates
Role in non pregnant females and males
19__-shown pit extract could stimulate milk
production in rabbits
__________stimulate PRL directly
Hyperprolactinemia and PRL secreting pit tumors
are common in women of reproductive age
Serum ____ increase at puberty ( FSH and LH)
PROLACTIN
Effects growth and differentiation of _______
__________
Hair and __________ glands in mammals
Brood patch/__________ Devt in birds
Evidence to suggest a role in testicular function
Hypophosectomy of adult rats causes a loss of
____________ receptors and loss of testes
response to LH
PRL needed for __________
PROLACTIN
Plasma levels only a bit higher in women
___________of conc. ranges in sexes
Secreted __________
Half life in blood of ________ min
Night time surge (like GH)
____________ to GH surge
PROLACTIN
Found _________in pit. and plasma
CHO groups vary among species- this
heterogeneity accounts ______
____________
Similar to GH, but different actions
Breast feeding women-________GH
Acromegaly only occasionally have
_________
PROLACTIN
All cells express ______ receptors
although the anterior pituitary is the
major source of prolactin, the hormone
is synthesized and secreted in
_____________.
Overall, several __________different
actions have been reported for
_________in various species.
PRL
critical role of prolactin in ________ has
been confirmed in mice with targeted
deletions in the prolactin gene.
Female mice that are ________for the
deleted prolactin gene (and produce
roughly half the normal amount of
prolactin) show failure to lactate after
their first pregnancy.
PROLACTIN
Prolactin also appears important in
several
non-lactational aspects of _____________
In some species (rodents, dogs, skunks),
prolactin is necessary for maintenance of
_____________ (ovarian structures that
secrete progesterone).
PROLACTIN
Mice that are __________
for an inactivated prolactin gene and
thus incapable of secreting prolactin
are i_________ due to
defects in ovulation, fertilization,
preimplantation development and
implantation.
PROLACTIN
Effects on Immune Function
The PRL receptor is widely expressed by
________cells, and some types of
lymphocytes synthesize and secrete PRL.
These observations suggest that _____ may
act as an autocrine or paracrine modulator
of immune activity.
Interestingly, mice with homozygous deletions of
the PRL gene ___________ significant
abnormalities in immune responses.
PROLACTIN
Effects on Immune Function
A considerable amount of research is in
progress to delineate the role of PRL in
normal and pathologic immune responses.
It appears that prolactin has
a__________role in several aspects of
immune function, but is not ____________
for these responses.
PROLACTIN
Control of Prolactin Secretion
In contrast to what is seen with all the other
pituitary hormones,
________________________ suppresses prolactin
secretion from the pituitary.
There is usually a hypothalamic “_______" set on
the lactotroph, and prolactin is secreted only
when the brake is released.
PROLACTIN
Control of Prolactin Secretion
If the pituitary stalk is cut, prolactin
secretion __________, while secretion
of all the other pituitary hormones
______dramatically due to loss of
hypothalamic releasing hormones.
PROLACTIN
Control of Prolactin Secretion
Dopamine
serves as the major ________-inhibiting
factor or brake on prolactin secretion.
Dopamine is secreted into portal blood by
hypothalamic neurons, binds to receptors
on lactotrophs, and inhibits both the
synthesis and secretion of ____________
PROLACTIN
Control of Prolactin Secretion
Agents and drugs that interfere with
________ secretion or receptor
binding lead to __________
secretion of prolactin.
PROLACTIN
In addition to tonic inhibition by
dopamine, PRL secretion is positively
regulated by several hormones,
including _____ and _______.
Stimulation of the _______ and
mammary gland, as occurs during
nursing, leads to prolactin release.
PROLACTIN
_________ provide a well-studied
positive control over prolactin
synthesis and secretion. The increasing
blood concentrations of estrogen
during late pregnancy appear
responsible for the elevated levels of
prolactin that are necessary to prepare
the mammary gland for lactation at
the end of gestation.
What Is a Prolactinoma?
benign tumor of the pituitary gland that
produces PRL
____________ type of pituitary tumor.
Symptoms of prolactinoma are caused by too
much _________in the blood
(hyperprolactinemia) or by pressure of the
tumor on surrounding tissues.
How Common Is Prolactinoma?
Autopsy studies indicate that ____% of the U.S.
population have small pituitary tumors.
_______ percent of these pituitary tumors produce
prolactin, but most are not considered clinically
significant.
Clinically significant pituitary tumors affect the
health of approximately 14 out of 100,000
people.
What Causes Prolactinoma?
Although research continues to unravel
the mysteries of disordered cell
growth-the cause of pituitary tumors
________________________.
Most pituitary tumors are sporadic—
they are not ____________ passed
from parents to offspring.
What Are the Symptoms?
In women, high blood levels of PRL often cause
_________________________________________.
In some women, periods may disappear altogether.
In others, periods may become irregular or
menstrual flow may change.
Women who are not pregnant or nursing may
begin ________________________________.
Some women may experience a loss of libido
(interest in sex). Intercourse may become painful
because of _________________________.
What Are the Symptoms?
In men, the most common symptom of
prolactinoma is ___________.
Because men have no reliable indicator such as
menstruation to signal a problem, many men
delay going to the doctor until they have
headaches or eye problems caused by the
enlarged pituitary pressing against nearby eye
nerves.
They may not recognize a gradual loss of sexual
function or libido.
Only after treatment do some men realize they had a
problem with sexual function.
What Else Causes Prolactin To Rise?
In some people, high blood levels of prolactin can be traced
to causes other than a pituitary tumor.
__________________ -PRL secretion in
the pituitary is normally suppressed by
dopamine.
Drugs that block the effects of ______ at
the pituitary or deplete ______stores in
the brain may cause the pituitary to
secrete prolactin.
What Else Causes Prolactin To Rise?
In some people, high blood levels of prolactin can be traced
to causes other than a pituitary tumor.
These drugs include the major tranquilizers
trifluoperazine (Stelazine) and haloperidol
(Haldol); metoclopramide (Reglan), used to
treat gastroesophageal reflux and the
nausea caused by certain cancer drugs; and
less often, alpha methyldopa and reserpine,
used to control
What Else Causes Prolactin To Rise?
In some people, high blood levels of prolactin can be traced to causes
other than a pituitary tumor.
__________Pituitary Tumors
Other tumors arising in or near the
pituitary—such as those that cause
acromegaly or Cushing's syndrome—may
block the flow of ____________ from the
brain to the prolactin-secreting cells.
What Else Causes Prolactin To Rise?
In some people, high blood levels of prolactin can be traced to causes
other than a pituitary tumor.
________________ Increased prolactin levels are
often seen in people with hypothyroidism, and
doctors routinely test people with
hyperprolactinemia for hypothyroidism.
_____________________ also can cause a modest
increase in the amount of prolactin in the blood.
How is Prolactinoma Diagnosed?
A doctor will test for prolactin blood
levels in women with unexplained
milk secretion (_________) or
irregular menses or infertility, and
in men with impaired sexual
function and, in rare cases, milk
secretion.
How is Prolactinoma Diagnosed?
If prolactin is high, a doctor will test
_________ function and ask first about
other conditions and medications known to
raise prolactin secretion.
The doctor will also request a MRI which is
the most sensitive test for detecting
pituitary tumors and determining their
size. MRI scans may be repeated
periodically to assess tumor progression
and the effects of therapy.
How is Prolactinoma Diagnosed?
___________________ (CT scan) also gives an
image of the pituitary, but it is less sensitive than
the ________
In addition to assessing the size of the pituitary
tumor, doctors also look for damage to
surrounding tissues, and perform tests to assess
whether production of other pituitary hormones
is normal. Depending on the size of the tumor,
the doctor may request an ________ with
measurement of visual fields.
How Is Prolactinoma Treated?
Medical Treatment
goal of treatment is to return _____
secretion to normal, reduce tumor size,
correct any visual abnormalities, and
restore normal pituitary function.
In the case of very large tumors, only partial
achievement of this goal may be possible.
Because _______is the chemical that normally
inhibits prolactin secretion, doctors may
treat prolactinoma with ___________e or
cabergoline, drugs that act like __________
How Is Prolactinoma Treated?
Medical Treatment
This type of drug is called a __________ agonist.
These drugs shrink the tumor and return
prolactin levels to normal in approximately
____% of patients.
Both have been approved by the FDA for the
treatment of hyperprolactinemia.
____________is the only dopamine agonist
approved for the treatment of infertility. Another
dopamine agonist, pergolide, is available in the
U.S., but is not approved for treating conditions
that cause high blood levels of prolactin.
How Is Prolactinoma Treated?
Medical Treatment
Bromocriptine treatment should not be
___________ without consulting a qualified
endocrinologist.
Prolactin levels often rise again in most
people when the drug is discontinued.
In some, however, prolactin levels remain
normal, so the doctor may suggest reducing
or discontinuing treatment every two years
on a trial basis.
How Is Prolactinoma Treated?
Medical Treatment
Cabergoline is also associated with side effects such as
nausea and dizziness, but less common and less
severe than with bromocriptine.
As with bromocriptine therapy, side effects may be
avoided if treatment is started slowly.
How Is Prolactinoma Treated?
Surgery
Surgery should be considered if medical therapy
cannot be tolerated or if it ______to reduce PRL
levels, restore normal reproduction and pituitary
function, and reduce tumor size.
If medical therapy is only partially successful, this
therapy should continue, possibly combined with
surgery or radiation.
The results of surgery depend a great deal on tumor
size and PRL level as well as the skill and
experience of the neurosurgeon.
How Is Prolactinoma Treated?
Surgery
The________the prolactin level, the lower the
chance of normalizing serum prolactin. In the
best medical centers, surgery corrects prolactin
levels in 80% of patients with a serum PRL less
than 250 ng/ml.
Even in patients with large tumors that cannot be
completely removed, drug therapy may be able
to return serum prolactin to the normal range
after surgery. Depending on the size of the tumor
and how much is removed, studies show that 2050 % will recur, usually within __ years.
How do I choose a skilled neurosurgeon?
Because the results of surgery are so dependent on
the skill and knowledge of the neurosurgeon, a
patient should ask the surgeon about the number
of operations he or she has performed to remove
pituitary tumors, and for success and
complication rates in comparison to major
medical centers.
The best results come from surgeons who have
performed many
___________________________ of such
operations.
How Does Prolactinoma Affect Pregnancy and Oral
Contraceptives?
If a woman has a small prolactinoma, there is
no reason that she cannot conceive/have a
normal pregnancy after successful medical
therapy.
The pituitary enlarges and prolactin
production increases during normal
pregnancy in women _____________
____
How Does Prolactinoma Affect Pregnancy and Oral
Contraceptives?
Women with _____-secreting tumors may
experience further pituitary enlargement
and must be closely monitored during
pregnancy. However, damage to the
pituitary or eye nerves occurs in less than
__% of pregnant women with
prolactinoma.
In women with large tumors, the risk of damage to
the pituitary or eye nerves is greater, and some
doctors consider around 25%