- Central Idea
- hypothalamus
- 7
- GHRH
- prolactin releasing hormone
- prolactin inhibiting hormone (dopamine)
- ACTRH
- TRH
- GRH
- somatostatin
- inhibits
- anterior pituitary
- pancreas
- GI
- gastrin
- cholecystokinin
- secretin
- motilin
- VIP
- GIP
- pituitary
- anterior
- 5/6
- somatotrophs
- lactotrophs
- prolactin
- 199 amino acids
- prolactinoma
- symptoms
- endocrine: milk production, irregular menses, sexual dysfunction
- mass effect: bitemporal hemianopia, nausea, vomiting
- Tx: bromocriptine / cabergoline, surgery
- corticotrophs
- ACTH
- 39 amino acids
- binds to the plasma membrane of adrenocortical calls, increasing cAMP and activating protein kinase —> cortisol release
- thyrotrophs
- gonadotrophs
- posterior
- ADH
- 9 amino acid polypeptide
- synthesised in the supra-optic nucleus of the hypothalamus
- you feel SUPeR when you’re drunk and don’t secrete ADH : SUPRa-optic nucleus
- oxytocin
- also 9 amino acids
- released in response to nipple stimulation
- synthesised in the paraventricular nucleus of the hypothalamus
- pregnant women have PARity : PARaventricular nucleus
- anatomy
- located in hypophyseal (pituitary fossa) / sella turcica
- anterior connects to posterior via short portal veins
- anterior connects to hypothalamus via long portal veins through the infundibulum
- body of sphenoid below
- cavernous sinus lateral
- parathyroid
- PTH
- produced in chief cells
- actions
- stimulates osteoclasts
- increases liver and kidney conversion of vit D3 to 1, 25-hydroxycolecalciferol
- increases GI Ca and phosphate absorption
- adrenals
- cortex GFR - salt, sugar, sex
- Glomerulosa
- mineralocorticoids
- aldosterone
- hyperaldosteronaemia
- types
- Primary
- Secondary
- cardiac/renal failure, MH, renal artery stenosis
- renin high
- aldosterone upregulates Na/K pump in DCT and CD —> Na and H20 retention, K and H excretion
- metabolic alkalosis, hypokalaemia, hypertension, hypervolaemia
- Tx: spironolactone (aldosterone antagonist)
- hypoaldosteronaemia
- types
- primary
- Addison’s
- most commonly autoimmune
- CRISIS Tx: ABC, hydrocortisone, fludrocortisone, dextrose (normally hypoglycaemic)
- secondary
- short synacthen test
- ACTH given and cortisol and/or aldosterone levels measured
- if primary, cortisol/aldosterone levels won’t rise
- if secondary, they will rise
- Fasciculata
- glucocorticoids
- cortisol
- hypercorticolism
- primary
- secondary
- Cushing’s disease
- ACTH secreting pituitary adenoma
- 80% of Cushing’s syndrome cases
- tertiary
- hypocorticolism
- also Addison’s
- CAH
- Waterhouse-Friderichsen syndrome
- bilateral adrenal haemorrhage w. severe meningococcal disease
- withdrawal of corticosteroid treatment
- 90%
- corticosterone
- Reticularis
- androgens
- testosterone
- 5%
- 95% produced by testes/ovaries
- dihydrotestosterone
- androstenedione
- medulla
- chromaffin cells
- 80% adrenaline
- 20% noradrenaline
- phaeochromocytoma
- normally norad, may secrete adrenaline or dopamine
- Tx: alpha or alpha + beta blockers, never just beta (can get severe hypertension by unopposed alpha stimulation, surgery
- small amount of dopamine
- formation
- phenylalanine
- L-tyrosine rate limiting step
- L-DOPA
- dopamine —> (dopamine beta-hydroxylase) —>
- ‘post tour depression DNA’
- thyroid
- hypothyroidism
- causes
- genetic
- acquired
- developing world: iodine deficiency
- Hashimoto’s thyroiditis
- surgery
- drugs
- radioiodine / excessive iodine
- pituitary disease
- hypothyroid crisis
- Tx: IV T3, NG T4, 100mg hydrocortisone
- hyperthyroidism
- causes
- 99% Graves disease
- carcinoma
- Tx
- antithyroid
- carbimazole
- propylthiouracil
- CENTRAL: inhibits thyroperoxidase
- PERIPHERAL: inhibits conversion of T4 to T3
- beta blockers
- symptomatic tx
- propranol may also inhibit conversion of T4 to T3
- radioactive iodine
- surgery
- thyroid storm
- ABC
- cooling
- hydrocortisone 100mg
- potassium iodide
- carbimazole
- plasmapheresis in most severe cases
- hormones
- T3 & T4
- bound to thyroglobulin inside the thyroid
- bound to thyroid binding globulin in the blood
- ‘gives me the tee-bee-gee-bees’
- calcitonin
- produced by parafollicular C cells
- inhibit osteoclast activity
- reduces tubular reabsorption of Ca and phosphate
- ‘Calci-tone-down'