Labs 8-13 Flashcards
How does GH affect plasma glucose levels?
GH promotes increased blood sugar (counter-insulin effects)
Why does GH hypersecretion increase risk of diabetes mellitus?
GH promotes increased blood glucose
hyperglycemia –> hyperinsulinemia
increased risk of insulin resistance and diabetes
what are the symptoms of GH hypersecretion?
gigantism, acromegaly (bone thickening), enlargement of hands and feet, protrusion of lower jaw, increased body hair and glucose tolerance
describe effects of somatotrope tumor
GH hypersecretion
gigantism, acromegaly –> risk for organomegaly
T/F: you can measure GH levels at a certain time to diagnose a defect
FALSE - GH secretion is pulsatile, so pointless to measure at a certain time period. have you observe changes in GH secretion in response to oral glucose administration
in normal patients, oral glucose administration should do what to GH levels?
decrease GH secretion
GH promotes glucose secretion so if you take oral glucose, you don’t need GH stimulating more glucose production
what is cold intolerance an indicator of?
TRH defect (low metabolism, TSH, T3/T4)
how does GH hypersecretion affect TSH production?
GH hypersecretion = Somatostatin increases (it inhibits GH and wants to bring it down) = decreases TSH production
SS inhibits TSH
T/F: SS stimulates TSH
FALSE - inhibits
Why do patients with pituitary tumors have headaches “behind their eyes”?
pituitary tumor mass enlargens in sella turcica –> vision defects, headache
can impinge on optic chiasma and cranial nerves
T/F: acromegaly TYPICALLY associates with hypotension
FALSE - hypertension
What is a possible treatment for GH hypersecretion?
SS analogs
How do you calculate the expected heigh of a child base on the heights of the parents?
avg the parents and -2.5 if patient is a girl, +2.5 if patient is a boy
in normal patients, on the onset of puberty, GnRH will increase what hormones? How will that affect males specifically?
GnRH increases FSH/LH production at the onset of puberty
in males: stimulates testes growth –> testosterone
T/F: GnRH secretion is pulsatile
TRUE
How would you measure GnRH secretions? (that a patient’s GnRH levels are normal)
Observe changes in FSH/LH levels with an injection of GnRH
T/F: prolactin (excessive) stimulates GnRH levels
inhibits
what is the clinical significance of decreased GnRH levels during high prolactin? (ex. nursing mothers)
During nursing, mothers have high prolactin that allows for good milking. GnRH (FSH/LH) is decreased to prevent pregnancy (cause having a pregnant nursing mother is bad –> very little nutrition for mom)
what is constitutional delay?
physical and sexual maturation delay
what disease is indicative of largely increased urine output?
diabetes insipidus
what are the urine and plasma osm levels in a patient with diabetes insipidus?
urine: low osm, hypotonic urine, large volume
plasma: high osm, hypernaturemia
what is polyuria
increased urine output
as seen in diabetes insipidus
how does diabetes insipidus affect heart rate, blood pressure, thirst?
polyuria –> decrease total body water, plasma vol and BP
baroreceptors sense decreased BP –> stimulate SNS to increase HR (tachycardia)
increase thirst (polydypsia)
what type of IV fluids should be given to patient with diabetes insipidus?
isotonic dextrose solution
dextrose metabolizes and leaves behind fluids (water) and decrease plasma osm
can also administer synthetic ADH to increase water retention
why does prolactinoma decrease menstruation?
increased prolactin = decreased GnRH = decrease FSH/LH –> no periods
what treatments can be used for patients with prolactinomas?
what are the 2 examples used in lab?
dopamine (PIF) agonists
ex. bromocriptine
ex. cabergoline (longer half life)
T/F: TRH stimulates prolactin
TRUE
