Pituitary Flashcards

1
Q

Anterior lobe of pituitary

A

Rathke’s pouch
Ectodermal diverticulum

Hormones: “FLAT PiG”

FSH
LH
ACTH
TSH
Prolactin
Intermidate – MSH
GH
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2
Q

Posterior lobe of pituitary

A

Invagination of hypothalamus – neuroectoderm

ADH
Oxytocin

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3
Q

ADH

A

Decrease urine output
Vascular constriction

Increase ADH: nicotine, opiates

Decrease ADH: ethanol, atrial natriuretic factor, decrase serum osmolality

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4
Q

Oxytocin

A

Uterine contraction – induced by cervix dilation

Milk ejection – stimulated by suckling

Inhibited by alcohol and stress

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5
Q

GnRH

A

Pulsatile release leads to FSH and LH secretion

Inhibited by prolactin

Continuous GnRH – inhibits FSH and LH

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6
Q

FSH

A

Granulosa cell follicle development
Spermatogenesis

Inhibited by inhibin

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7
Q

LH

A

Progesterone production
Theca lutein cells
-ovulation
-form corpus luteum

Leydig cells -> testosterone

Inhibited by progesterone and testosterone

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8
Q

ACTH

A

Release stimulated by CRH and stress
Inhibited by cortisol

Acts on adrenal cortex to release cortisol

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9
Q

MSH

A

Intermediate lobe of pituitary

-> melanin release by melanocytes

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10
Q

TRH

A

Stimulates TSH release, acts on thyroid to release T3, T4

Inhibited by T3, T4

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11
Q

GH

A

Stimulated by GHRH, exercise, sleep, puberty, hypoglycemia, estrogen, stress, endogenous opioids

Cause:
Release of IGF-1 -> growth 
Decreased glucose uptake
Increased protein synthesis
Increased organ size
Increase lean body mass

Inhibited by GHIH (somatostatin), somatomedins, IGF1, obesity, pregnancy, hyperglycemia

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12
Q

Prolactin

A

Stimulated by TRH

Causes milk production and secretion, breast development

Inhibits ovulation
Inhibits GnRH

Release inhibited by dopamine

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13
Q

POMC

A

Precursor to ACTH and MSH

Contains hormonal peptides sequence for: lipotropin, beta-endorphin

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14
Q

Primary adrenal insufficiency

A

Production of cortisol low

Hypothalamus and pituitary make ACTH, trying to stimulate the adrenals to make more cortisol

When ACTH concentration is excessive, MSH receptors in skin are stimulated -> skin hyperpigmentation

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15
Q

Hyperprolactinemia

A

MC anterior pituitary hormone abnormality

Causes by:
Pregnancy/nipple stimulation
Stress – physical or psychological
Prolactinoma – assoc w/ bitemporal hemianopia
Dopamine antagonists – anti psychotics (haloperidol, risperidone), domperidone, metoclopramide

Premenopausal female sx: hypogonadism -> infertility, oligo/amenorrhea, rarely galactorrhea

Post menopausal: no sx – already hypogonadal

Males: hypogonadism (low T) -> decreased libido, impotence, infertility (low sperm counts), gynecomastia, rarely galactorrhea

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16
Q

Pituitary adenoma

A
Prolactinoma ->
Amenorrhea
Galactorrhea
Low libido
Infertility
Bitemporal hemianopia

Tx: bromocriptine, cabergoline (DA agonists)
Surgical resection

17
Q

Acromegaly

A

Too much GH
Adult

Large tongue – deep furrows, indentations (teeth)

Increased spacing of teeth
Deep voice
Large hands and feet
Coarse facial features
Impaired glucose tolerance -> DM

Dx: elevated IGF-1
OGTT – check GH level not glucose
-normally glucose suppresses GH

Tx: surgical resection
Octreotide

18
Q

Gigantism

A

Too much GH in kids

Excess bone growth of linear bones

Tall and big children

Dx: elevated IGF-1
OGTT – check GH level not glucose
-normally glucose suppresses GH

Tx: surgical resection
octreotide

19
Q

Somatostatin

A

D cells in GI mucosa
Pancreatic islet cells
Nervous system

Actions:
Reduces splanchnic blood flow, reduces GI motility, gallbladder contraction, inhibits secretion of most GI hormones
Deceases exocrine secretions in the pancreas
Decreases hormone secretion in CNS, PNS, endocrine organs

20
Q

Clinical uses of somatostatin analogs

A

octreotide, somatostatin LAR, lanreotide –P

pituitary excesses (except prolactin): acromegaly, thyrotropinoma, ACTH-secreting tumors

GI endocrine excess: Zollinger-Ellison Sn, carcinoid sn, VIPoma, glucagonoma, insulinoma

Diarrheal diseases

Need to reduce splanchnic circulation: portal hypertension (bleeding varices), bleeding peptic ulcers

21
Q

Sheehan syndrome

A

Postpartum hemorrhage -> underperfusion of pituitary

Pituitary necrosis and hypopituitarism

Aglactorrhea d/t deficiency of prolactin
Amenorrhea after delivery
Secondary hypothyroidism -> fatigue, cold intolerance, wt gain
Hyponatremia (rare)