B6-064 Growth Hormone/Prolactin Flashcards by Felicia Jones

the arcuate nucleus in the hypothalmus secretes what in the GH pathway?

growth hormone releasing hormone (GHRH)

How well did you know this?

Not at all

Perfectly

secondary triggers for the release of GHRH [4]

increased amino acid levels
hypoglycemia
decreased fatty acids in blood
exercise

How well did you know this?

Not at all

Perfectly

GHRH goes into the […] to stimulate somatotropes to secrete GH

adenohypophysis

How well did you know this?

Not at all

Perfectly

GHRH goes into the adenohypophysis to stimulate […] to secrete GH

somatotropes

How well did you know this?

Not at all

Perfectly

GHRH goes into the adenohypophysis to stimulate somatotropes to secrete […] into the blood

growth hormone (GH)

How well did you know this?

Not at all

Perfectly

how does GH stimulates the production of IGF type 1

some GH binds to tyrosine kinase-like receptor
stimulates JAK/STAT activation
STAT goes into the nucleus and stimulates the production of IGF1 (insulin growth factor 1)

How well did you know this?

Not at all

Perfectly

some GH stimulates […] in the liver

gluconeogenesis

How well did you know this?

Not at all

Perfectly

how does GH trigger lipolysis

GH binds to hormone sensitive lipase

HSL initiates lipolysis –> more glycerol available for gluconeogenesis

How well did you know this?

Not at all

Perfectly

[…] stimulates amino acid uptake

GH via IGF1

**activate channels for amino acids on skeletal cell membranes

How well did you know this?

Not at all

Perfectly

stimulates amino acids to link together to produce myofibrils –> hypertrophy

IGF1

How well did you know this?

Not at all

Perfectly

regulates osteoblasts and osteoclasts to encourage appositional growth and endochondral ossification of bones

IGF1

How well did you know this?

Not at all

Perfectly

IGF1 stimulates the production of […], which is crucial to endochondral ossification

collagen type 1

How well did you know this?

Not at all

Perfectly

stimulates chondroblasts to differentiate, increase in size, and proliferate resulting in interstitial growth

IGF1

How well did you know this?

Not at all

Perfectly

modified apocrine glands designed to produce milk

mammary glands

How well did you know this?

Not at all

Perfectly

simulates the production of milk by alveolar cells

prolactin

How well did you know this?

Not at all

Perfectly

tube-like structures made up of alveolar glands

lobules

How well did you know this?

Not at all

Perfectly

anchor the breast to the posterior wall

suspensory ligaments

How well did you know this?

Not at all

Perfectly

little tubes that drain the lobules

lactiferous ducts

How well did you know this?

Not at all

Perfectly

dilation of lactiferous duct just behind the nipple

lactiferous sinuses

How well did you know this?

Not at all

Perfectly

prolactin is synthesized by […] in the anterior pituitary

lactotropes

How well did you know this?

Not at all

Perfectly

prolactin is synthesized by lactotropes in the […]

anterior pituitary

How well did you know this?

Not at all

Perfectly

prolactin inhibiting hormone (dopamine) are secreted by the

hypothalamus

**go through hyophyseal portal system to anterior pituitary

How well did you know this?

Not at all

Perfectly

binds to D2 receptors to inhibit lactotropes

prolactin inhibiting hormone
[dopamine]

How well did you know this?

Not at all

Perfectly

thyrotropin-releasing hormone (TRH) is secreted by the […] nucleus

paraventricular nucleus

How well did you know this?

Not at all

Perfectly

binds to specific receptors to stimulate prolactin secretion via lactotropes

thyrotropin-releasing hormone (TRH)

how does breast feeding provide a direct stimulus of prolactin? [2]

baby suckling triggers mechanoreceptors to release oxytocin --> stimulates production of prolactin baby sucking stimulates PVN to release more TRH --> stimulates lactotropes to produce prolactin

high levels of [...] are extremely important to prolactin stimulation

estrogen

estrogen stimulates the production of prolactin directly via the [...] and indirectly by [...]

direct: via the lactotropes indirect: inhibits the arcuate nucleus from secreting PIH (dopamine)

extremely high levels of estrogen inhibit [...] effect on alveolar cells

prolactin's **as estrogen levels fall after birth, prolactin starts effecting alveolar cells

prolactin activates the JAK/STAT pathway to transcribe mRNA into [2]

milk proteins: casein, lactoferin kinases that phosphorylate different channels on the cell membrane to allow ions, IgA, lipids, and vitamins into breast milk

GH and prolactin are both secreted by the

anterior pituitary

stimulates linear growth and muscle mass via IGF1 secretion by liver

increases insulin resistance

GH is released in pulses in response to

GHRH

secretion of GH is increased in what conditions?

sleep hypoglycemia stress puberty exercise

secretion of GH is decreased in what conditions?

aging obesity hyperglycemia somatostatin

excess secretion of GH (i.e. due to pituitary adenoma) causes

acromegaly in adults gigantisim in children

treatment for excess secretion of GH

somatostatin analog (octreotide) surgery

how does IGF1 affect bone? [6]

increases: amino acid uptake protein synthesis DNA/RNA synthesis chondroitin sulfate collagen cell size and number

how does IGF1 affect skeletal muscle?

increases: amino acid uptake protein synthesis

how does IGF1 affect adipose?

decreased glucose uptake increases lipolysis

structurally homologous to GH

prolactin

stimulates milk production in breast

prolactin

inhibits ovulation in females and spermatogenesis in males by inhibit GnRH synthesis

prolactin

excessive amount of [...] is associated with decreased libido

prolactin secretion from the anterior pituitary is inhibited by

dopamine

TRH increases [...] secretion

prolactin

inhibit prolactin secretion and can be used in treatment of prolactinoma

dopamine agonists

what drug classes stimulate prolactin secretion?

dopamine antagonists estrogens

excess GH in adults, typically caused by pituitary adenoma

acromegaly

increased GH in children causes

gigantism **due to increased linear bone growth

stimulates IGF-1 secretion from liver

symptoms of acromegaly

enlargement of hands and feet macroglossia macrognathia impaired glucose tolerance

GH stimulates [...] receptors

non-tyrosine kinase JAK/STAT pathway

IGF-1 signals through [...] receptors

tyrosine kinase

treatment for acromegaly and hyperprolactinemia

octreotide

how does IGF-1 enter systemic circulation?

hepatic vein --> IVC

GH stimulates the production of [...] in the liver

IGF-1

what hormones use a receptor tyrosine kinase pathway? [4]

**in**sulin I**GF**-1 PD**GF** F**GF** **G**et **F**ound **IN** the MAP

postpartum symptoms of fatigue anorexia poor lactation loss of pubic and axillary hair

Sheehan syndrome (postpartum hypopituitarism)

prolactinoma causes [...] due to compression of the optic chiasm

bitemporal hemianopia

symptoms of prolactinoma in men [3]

decreased libido erectile dysfunction gynecomastia

symptoms of prolactinoma in women [4]

decreased libido galactorrhea amenorrhea infertility

Sheehan syndrome is caused by

ischemia necrosis of the pituitary gland secondary to significant blood loss during delivery

in Sheehan syndrome, inability to lactate is caused by

decreased prolactin

in Sheehan syndrome, amenorrhea is caused by

decreased LH/FSH

cause headaches and bilateral hemianopia

prolactinomas

why does a prolactinoma in women cause amenorrhea and infertility?

inhibition of gonadotropin releasing hormone due to excessive prolactin

used to treat prolactinoma

dopamine agonists (bromocriptine, cabergoline)

medications that can be used to stimulate prolactin secretion

dopamine antagonists (antipsychotics, metoclopramide) estrogens (OCPs, pregnancy)