Pituitary Physiology Flashcards
What end organs does testosterone have an effect on?
Muscle Bone Libido Penis Hair follicles
What end organs are affected by Oestrogen?
Bone
Fat
Vagina
Heart and Liver
What hormones are involved in the steroid axis?
Corticotrophin Releasing Hormone (CRH)
ACTH
Cortisol
What does cortisol help the body to do?
Regulate glucose levels
Increase fat
Fight infection
Respond to stress
What hormone stimulates release of FSH/LH from the pituitary?
Gonadotrophin releasing hormone
GnRH
How is prolactin release stimulated from the pituitary?
If dopamine is decreased
Dopamine inhibits release of prolactin
How do we test if too much or too little hormone is being produced?
Blood tests
How do we test if the pituitary etc have become too large?
Imaging
US/MRI
What two types of hormone are considered “paired” hormones?
Central/pituitary
and
Peripheral
Give an example of paired hormones
ACTH and Cortisol
TSH and Thyroxine
FSH/LH and Testosterone/Oestrogen
GH and IGF-1
What structures could an enlarged pituitary gland potentially compress?
Optic chiasm
Sphenoid Bone
Cranial Nerves III, IV, VI
Internal Carotid Arteries
What structures are found in the cavernous sinus?
CN III, IV, VI
Internal Carotid arteries
What type of test is carried out if it is suspected there is too much hormone?
A suppression test
=> the level of hormone not changing would be a positive result
What test can be carried out if too much little hormone is suspected?
A stimulation test
Explain the stimulation from an Insulin Stress Test
Pt given insulin to elicit hypoglycaemia and stress response
=> Cortisol and GH should be released
