basic endocrinology Flashcards
four main groups of hormone receptors
- G-protein coupled receptors
- Receptor tyrosine kinase families
- receptors associated with tyrosine kinase activity
- steroid hormone receptors
what do GPCRs do
sensors of sensory stimuli ions, neurotransmitters, chemokines, hormones, prescribed drugs
what is an example of a receptor tyrosine kinase family
insulin receptor
examples of cytokine receptors
- prolactin receptor
- growth hormone receptor
where are steroid receptors usually found
intracellular - either in cytoplasm or nucleus
examples of the nuclear receptor family
estrogen and androgen receptors
what does steroid receptor complex binding to DNA response elements result in
changes in gene transcription
does pituitary gland hormones take part in negative feedback
yes
what does the ability to accurately measure hormone levels depend on
- pattern of secretion
- presence of carrier proteins
- interfering agents
- stability of hormone
- absolute concentrations
what does normal TSH mean about the thyroid
normal thyroid
what does raised TSH say about the thyroid
hypothyroid
what does suppressed TSH say about the thyroid
hyperthyroid
why wouldn’t you measure thyroid hormone axis in sick people
because thyroid function is affected if someone is acutely unwell
how can we assess pituitary function
- 9am cortisol
- FT4, FT3, TSH
- prolactin
- IGF1
- LH, FSH, E2/ Testosterone
- U&E, plasma/urine osmolality
- dynamic tests
- imaging
what is the hypothalamic-pituitary-adrenal axis?
hypothalamus > secretes corticotropin-releasing hormone > anterior pituitary > secretes adrenocorticotropic hormone (ACTH) > adrenal cortex > secretes cortisol > multiple physiological effects
CORTISOL can negatively feedback to inhibit anterior pituitary and hypothalamus
is time relevant in taking a growth hormone measurement
yes
when should you measure testosterone
9am
what is prolactin secreted by
lactotroph cells of the anterior pituitary gland under tonic inhibition by hypothalamic dopamine
what is secretion of prolactin regulated by
a short loop negative feedback
what are the three major hormone groups produced by steroid hormone metabolism
- aldosterone
- cortisol
- testosterone
pathway of endocrine diagnosis
- history and examination
- screening biochemical test
- confirmatory biochemical test
- imaging and additional specialised test
- treatment
what does cortisol deficiency cause
- primary adrenal failure
- pituitary disease
what does excess cortisol cause
Cushing’s syndrome
- pituitary origin or adrenal origin
- can be caused by steroid abuse and also ectopic ACTH
