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  #1  
Old 02-26-2012
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Question Hormonal levels in Acromegaly

serum level of INSULIN(not IGF-1) and SOMATOSTATIN?
both normal? or only somatostatin increased?
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why would somatostatin be increased?
isnt that (octreotide) what we give to treat acromegaly?

i would think insulin increased (with decreased peripheral insulin sensitivity) and normal (if not, decreased) somatostatin.
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Quote:
Originally Posted by Dr.NickRiviera View Post
why would somatostatin be increased?
isnt that (octreotide) what we give to treat acromegaly?

i would think insulin increased (with decreased peripheral insulin sensitivity) and normal (if not, decreased) somatostatin.
because of negative feedback:
normally GH (IGF-1 more precisely) stimulate somatostatin release from hypothalamus to anterior pituitary inhibiting GH release.
accrding to kaplan
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Quote:
Originally Posted by kenlee View Post
because of negative feedback:
normally GH (IGF-1 more precisely) stimulate somatostatin release from hypothalamus to anterior pituitary inhibiting GH release.
accrding to kaplan
hmmmmmmmmmmmm
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Quote:
Originally Posted by Dr.NickRiviera View Post
hmmmmmmmmmmmm
OR
increased IGF1 stimulate somatostatin secretion so==> increased somatostatin.
increased somatostatin would decrease level of insulin.
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Quote:
Originally Posted by kenlee View Post
OR
increased IGF1 stimulate somatostatin secretion so==> increased somatostatin.
increased somatostatin would decrease level of insulin.
well we have insulin resistance for sure, so insulin levels have to be normal or increased.
i dont think we have decreased insulin in acromegaly.
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i dont think somatostatin inhibits insulin secretion.

id say increased somatostatin (due to increased GH)
and normal or increased insulin.
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Quote:
Originally Posted by Dr.NickRiviera View Post
i dont think somatostatin inhibits insulin secretion.

id say increased somatostatin (due to increased GH)
and normal or increased insulin.
somatostatin does inhibit insulin secretion
basically inhibits more or less all endocrine hormones such as insulin, glucagon, gastrin, also gallbladder contraction pancreatic fluid secretion etc.
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Old 02-27-2012
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anybody else has any other ideas?
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Quote:
Originally Posted by kenlee View Post
serum level of INSULIN(not IGF-1) and SOMATOSTATIN?
both normal? or only somatostatin increased?
thats a good question.

Well GH normally causes hyperglycemia, increased amino acid uptake and increased synthesis/release of IGF-1. The hyperglycemia then causes increased insulin release which will cause all tissues in the body to uptake it. As the name suggest it causes growth throughout the body.

Normally when glucose and IGF-1 reach a certain level they cause negative feedback inhibiting the further release of GH.

In acromegaly this negative feedback mechanism does not work at all. There is constant release of GH leading to hyperglycemia and constant synthesis/production of IGF-1.

So Insulin release will be increased due to constant hyperglycemia. Over the long run there will be Beta-cell burnout since they keep producing insulin and finally at some point they will stop making it. (yes beta cell burnout is a real term)!!!

Somatostatin will also be high. The body's normal response to high GH is to release somatostatin to inhibit GH secretion. But in acromegaly like I mentioned somatostatin has no effect. So you're probably wondering how the hell does Octreotide work then. The way it works is to increase Somatostatin to such high levels (levels not possible through our own body's mechanism) that it will inhibit GH secretion and even cause shrinkage of the adenoma. But it doesn't work in ALL patients although it works in most (about 60%). This is why Surgery is the first form of treatment. And if increased GH persists even after surgery (which it does suprisingly in some cases) then medications are used.

Sorry for such a long post....but the answer to your original question is that Insulin and somatostatin are BOTH increased. Remember though, in long standing disease though there can be Beta-cell burnout leading to diminished insulin levels.
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I agree with Haga. IGF-1 is there but the body is not being receptive to it, so basically GH, IGF-1, and Insulin are all increased. As Haga stated eventually Beta-cells do burn out and insulin will decrease but thats long term.

Acromegaly... I would take advantage of that at the gym
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Excessive GH will decrease the peripheral tissue sensitivity to Insulin that is called the ( anti insulin effect ) , and this will increase the blood glucose ( hyperglycemia ) then produce a compensatory hyperinsulinemia , SO insulin will increase .
Somatostatin acts opposite to the GHRH , so it decreases the secretion of GH by inhibitory mechanism , because GH increased so Somatostatin will increase by the action of high level of IGF-1 on hypothalamus .
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Quote:
Originally Posted by MARYAMB View Post
Excessive GH will decrease the peripheral tissue sensitivity to Insulin that is called the ( anti insulin effect ) , and this will increase the blood glucose ( hyperglycemia ) then produce a compensatory hyperinsulinemia , SO insulin will increase .
Somatostatin acts opposite to the GHRH , so it decreases the secretion of GH by inhibitory mechanism , because GH increased so Somatostatin will increase by the action of high level of IGF-1 on hypothalamus .
so wouldnt somatostatin now decrease insulin secretion?
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Quote:
Originally Posted by kenlee View Post
so wouldnt somatostatin now decrease insulin secretion?
i decrease it when it is secreted from the delta cells of pancreas, not in this case
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Quote:
Originally Posted by kenlee View Post
so wouldnt somatostatin now decrease insulin secretion?
When Glucose is present it causes depolarization of beta cells even in the presence of somatostatin. Once insulin is released it decreases glucose levels which will decrease the depolarization of beta cells and somatostatin will ensure that further insulin release does not occur at all.

Since hyperglycemia is present in acromegaly there is constant depolarization of the Beta cells which is why they keep releasing insulin.
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