Growth Hormone Excess and Physiology

Question 1

GH acts on the liver to make ___

Answer 1

IGF1:

Question 2

indirect and direct effects of growth hormon

Answer 2

indirect; IGF-1 stimulant is an anabolic agent. Protein. muscle, cartiglarge, and bone growth

direct: metabolic; lipolysis, carbohydrate issues causing hypoerglycermia, hyperinsulinism, ketogeneiss, sodium and water retension.

Question 3

growth hormone is antagonistic to ___ and synergistic with ___

Answer 3

antagonistic to insulin
synergistic with cortisol

Question 4

factors that stimulate GH secretion

Answer 4

fasting, deep ssleep, hypoglycemia, amino acids

Question 5

how does IGF1 affect GH secretioin

Answer 5

suppresses it, acts as a negative feedback loop

Question 6

factors that suppres GH secretion

Answer 6

IGF-1, hypothyroid, obesity, hyperglycemia

Question 7

Serum IGF-1 can be measured at any time to detect GH
__
Suppression test to diagnose GH ___

Stimulation test to diagnose GH ___

Answer 7

Serum IGF-1 can be measured at any time to detect GH
hypersecretion
Suppression test to diagnose GH hypersecretion

Stimulation test to diagnose GH hyposecretion

Question 8

most causes of acromegaly is due to ___

Answer 8

GH secretign pituitary adenoma

Question 9

the main outcome of acromegaly is generally the expansion. and proliferation of tissue. what results in their height? what about their facial features

Answer 9

pre-pubertal onset results in gigantism because growth plate remains open

• in acromegaly, yhou can have large nose, large lips, increased supraorbital ridges.

Question 10

what measurement of the hand can lead you to diagnosing excessive growth hormone?

Answer 10

measuring the thickness of skin at the back of the hand. if more than 3mm, might be due to excessive growth hormoe/acromegaly

Question 11

CV invovlvement of acromegaly

Answer 11

cardiomegaly (LVH), hypertension, ischemic disease, cardiomyopathy

Question 12

T/F to diagnose acromeglay, we should measure random serum growth hormone for diagnis. If it is high, we know that GH is excessive.

Answer 12

false. GH has episodic secretion to behin with. too variable in normals and acromegalics to dfiferentiate between normal from abnormal. to diagnose acromegaly, we need to SUPRESS (glucose) to diagnose hypersection

Question 13

what results of an OGTT would indicate acromegaly (excessive GH)

Answer 13

GH gets stimulated in response to hypoglycemia, and suppresses in response to hyperglycemia. DUring times of hypoglycemia (or hyperinsulinemia), the levels will rise to increase glucose.

when glucose is administered, the GH should reduce. If there is too much glc in the system but GH is still high, this would indicate hypersecretion

Question 14

in addition to the OGTT for acromegaly, what other test is key for acromegaly Dx?

Answer 14

serum IGF-1. if too high, would indicate a hypersecretion. Also can do an IGF1 supreession test. failure to suppress GH = autonomous secretion of GH

Question 15

how does somatostatin affect GH

Answer 15

it blocks GH.

Question 16

therapies for a GH-secreting tumor

Answer 16

surgery, radiotherapy, somatostatin analgogue, or a GH receptor blocker

Question 17

T/F we should treat acromegaly in all cases

Answer 17

ture. treatment improves morbidity and mortality. recall that acromegaly is not just being tall, it can cause CVD, sleep apnea, obesity.

Question 18

side effects to somatostatin analoques

Answer 18

recall that somatostatin inhibits GH release in the pituitary, but it also acts on the GI system (ex/ octreotide for varices). therefore, can get GI issues like diarrhea, nausea.

also can cause hypoglycmeia