Anterior Pituitary - Exam 3 Flashcards
The anterior pituitary is supplied by the ______ artery. The posterior pituitary is supplied by the _____.
anterior: superior hypophyseal artery and receives hypothalamic hormones through long portal vessels in vascular network
posterior: inferior hypophyseal artery and receives hypothalamic hormones to vascular network through DIRECT neural extension
Name the tropic hormones that are released by the AP and what hormone controls them in the hypothalamus
Hypothalamus -> AP
CRH->ACTH
TRH -> TSH
GnRH -> LH/FSH
Prolactin-releasing peptide -> Prolactin
Somatocrinin (stimulates) Somatostatin (inhibits) -> Growth hormone
Which hormone is usually in a SUPPRESSED state? What hormone is responsible for suppressing it?
Prolactin
is suppressed by prolactin-inhibiting factor (PIF) may be dopamine
Dopamine increases = _____ Prolactin. PRL remains in an inhibited state most of the time by _____
decreases
dopamine
What are the 5 types of endodrine CELLS in the AP, name them and what do they secrete?
somatotrophs = GH
lactotrophs = Prolactin
gonadotrophs = LH & FSH
corticotroph = ACTH
thyrotroph = TSH
What endocrine condition is commonly seen in chronic opioid users?
Hypopituitarism
63% of users will have this!
What is Prader-Willii syndrome?
rare genetic disorder that involves anorexia at birth to excessive weight gain preceding hyperphagia, and early severe obesity with hormonal deficiencies, behavioural problems, and dysautonomia. Growth hormone deficiency, hypogonadism, hypothyroidism, premature adrenarche, corticotropin deficiency, precocious puberty, and glucose metabolism disorders are the main endocrine dysfunctions observed
What is Kallmann syndrome?
a rare genetic disorder that prevents or delays puberty and causes a decreased sense of smell
What is Hypopituitarism?
Disorder in which all the hormones that are secreted in the AP do not function properly. S/S will present as a deficiency in those hormones.
GH: growth disorders
Gonadotropin: decreased sexual function, menstrual disorders etc etc
TSH: hypothyroidism in children and adults
ACTH: hypocortisolism
Prolactin: failure of lactation
Prolactin (PRL) is synthesized in _____. The MC cause of pituitary adenoma is ______.
lactotrophs
prolactinoma
Significant lactotroph cell hyperplasia develops during _____ in response to increased ____ and during first few months of lactation
pregnancy
estrogen
What are the normal serum levels of PRL? include men and women
men: 10-20
women: 10-25
PRL levels increase about tenfold during pregnancy and decline rapidly within 2 weeks of parturition UNLESS ?????. The increase in PRL is in response to the elevated ????. What stimulates an increase in PRL?
a women continues to breastfeed
estrogen and progesterone
Suckling
The magnitude of PRL increase is directly proportional to the degree of ????? due to estrogen - lactotrophs increase in pregnancy, therefore increasing the amount of PRL that can be released
preexisting lactotroph hyperplasia
Name 4 ways serum prolactin levels rise mildly and transiently
- Exercise, meals, sexual intercourse
- Breast exam, chest wall injury/infection (i.e. shingles)
- Minor surgical procedures, general anesthesia
- Stress of any kind - reduction of dopamine!
PRL secretion is _____. When is PRL at its highest?
pulsatile
occurring during non-REM sleep between 4-6am
circulating 1/2 life is 50 minutes
What are the effects of prolactin on lactation, reproductive function and sex drive
induces and maintains lactation
decreases repro function
suppresses sex drive
Reproductive function suppressed by ?????? also impaired gonadal steroidogenesis (LH/FSH). You will also see low ____ and _____.
inhibiting GnRH and gonadotropin secretion
low estrogen and anovulation
**_____ is the most common pituitary hormone hypersecretion syndrome in both men and women
Hyperprolactinemia
_____ are the most common cause of PRL levels >200 μg/L (normal level is about 10-20 for men and 10-25 for women). These are common in families with ____
PRL-secreting pituitary adenomas (prolactinomas)
MEN type 1 or 4
**Why would stalk compression cause hyperprolactinemia?
stalk compression would increase prolactin
kidney damage: increases prolactin
TRH increase: increases prolactin
**What are the causes of HYPERprolactinemia
Amenorrhea, galactorrhea, and infertility
decreased libido, weight gain, mild hirsutism
longterm: osteopenia and reduced muscle mass
**What are the hallmarks clinical presentation of hyperprolactinemia? What are some additional findings?
Hyperprolactinemia causes ____ and _____ in men. Name some clinical manifestations. Name some long term effects.
hypogonadotropic (decreased FSH/LH)
hypogonadism (decreased testosterone)
Decreased libido
Impotence/erectile dysfunction
Infertility
Gynecomastia
Galactorrhea - less common in men
longterm: osteopenia, reduced muscle mass, and decreased facial hair growth.