The Pituitary Gland- hypersecretion, hyposecretion and pituitary tumours Flashcards
List the hormones produced by the anterior pituitary.
TSH (thyroid stimulating hormone)
ACTH (adrenocorticotropic hormone)
LH (luteinizing hormone)
FSH (follicle stimulating hormone)
GH (growth hormone)
Prolactin
What does ACTH control?
Steroid production from the adrenal gland
List the hormones produced by the posterior pituitary.
Antidiuretic hormone
Oxytocin
RECAP- what is the role of antidiuretic hormone?
Urine production and rate.
RECAP- what does oxytocin do?
Assists in uterine contraction during delivery
What do LH and FSH do?
Stimulate the ovary for oestrogen and progestin production.
Stimulates testes for production of testosterone.
What role does prolactin have?
Milk secretion
Hypersecretion of GH can lead to what?
Acromegaly
Gigantism
->some say Goliath had gigantism because he was so tall. Also, he did not see the stone coming towards him shot by David suggesting there was compression of his optic chiasm from a pituitary tumour leading to bitemporal hemianopia.
Hypersecretion of ACTH can lead to what?
Cushing’s disease
Hypersecretion of prolactin can lead to what?
Hyperprolactinemia
If there is a tumour of the pituitary gland, what structure may it compress?
Optic chiasm
->this can cause bitemporal hemianopia
What is the main cause of hyper and hyposecretion?
Tumours
Tumours can also cause hyposecretion of hormones. List some of the hormones that are hyposerceted from tumours in the anterior pituitary.
FSH/LH
GH
ACTH
TSH
Tumours can also cause hyposecretion of hormones. List a hormone which is hyposerceted from tumours in the posterior pituitary.
Vasopressin
What can the posterior hyposecretion of vasopressin lead to?
Diabetes insipidus a.k.a Arginine Vasopressin Deficiency (AVD)
-> rare condition in which people produce a large amount of water and often feel thirsty
RECAP- what is acromegaly?
Overproduction of GH which causes widening of bones (not lengthening, that’s gigantism and that occurs before bones fuse in childhood).
What re some of the clinical features of acromegaly?
Spade like hands- rings often don’t fit anymore
Wide feet- complaints in shoes not fitting
Thick lips and tongue
Carpal tunnel syndrome
Sweating
Jaw more widely spaced- may be picked up by dentist
What are some of the complications of acromegaly?
Headaches- tumour size or excess GH
Optic chiasm compression
Diabetes mellitus
Hypertension
Cardiomyopathy
Sleep apnoea- due to large tongue
Colonic polyps
Accelerated osteoarthritis
What is the definitive test to diagnose acromegaly?
Glucose tolerance test
What should the glucose load do to GH in normal individuals having a glucose tolerance test?
Should supress GH
Sometime a screening test can be used before the diagnostic glucose tolerance test.
Raised levels of what suggest that the patient should go onto have a glucose tolerance test?
Elevated IGF-1 (insulin-like growth factor 1)
If the glucose tolerance test is positive, which further investigation is done and why?
MRI to see if the rets of the pituitary function is normal or if there is a mass
When would a pituitary tumour need to be removed more quickly?
If the vision of the patient is affected
Excess corticosteroids causes what?
Cushing’s syndrome