Biochemical Actions of Insulin in Sympathetic Stimulation! - USMLE Forums
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Old 12-11-2011
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Pancreas Biochemical Actions of Insulin in Sympathetic Stimulation!

sympathetic stimulation (adrenergic B2 receptor activation) results in:

skeletal muscle: increase glycogenolysis-contractility(tremor)
liver: increase glcogenolysis
hormone sensitive lipase (HSL) is also activated to increase level of TG in blood
pancreas: increase insulin


if insulin is also increasing with sympathetic stimulation so what it will do
I mean what will be the its action?
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I think that sympathetic stimulation, in general, does not result in an increase in insulin secretion from pancreas.
α2 receptors inhibit insulin release!
I believe that β2 receptor activation,specifically, does not increase insulin secretion either.

Is it written somewhere?
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Quote:
Originally Posted by Relid View Post
I think that sympathetic stimulation, in general, does not result in an increase in insulin secretion from pancreas.
α2 receptors inhibit insulin release!
I believe that β2 receptor activation,specifically, does not increase insulin secretion either.

Is it written somewhere?

yes pharmacology kaplan notes (page no.54)
during stress(exercise,fear or fight): B2 receptors stimulated
bronchodilation,vasodilation,gluconeogenesis occurs but b2 receptor activation also increase insulin secretion,what will be the its effect?
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Quote:
Originally Posted by riya_rai84 View Post
yes pharmacology kaplan notes (page no.54)
during stress(exercise,fear or fight): B2 receptors stimulated
bronchodilation,vasodilation,gluconeogenesis occurs but b2 receptor activation also increase insulin secretion,what will be the its effect?
wouldnt it be the fact that if insulin secretion is increased then it will lower the blood glucose levels.. thats y you have to be more careful when giving b blockers to diabetic.
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May be because insulin helps in uptake of glucose by the muscles so it is increased in fear and fright response..
We dont give beta blockers (specifically beta 1 blockers) to diabetics,because these can decrease HR,masking the S/S of hypoglycemia.
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Lol its simple must hear dr,turco biochem kaplan lectures he has made these things really easy ! Insulin stimulates glycolysis through which u get ATP( and further kreb cycle etc more ATP hope u know that pathway)
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I think it makes sense so glycolysis so more energy and also insulin stimulates GLUT4 formation ( late effects) and more entry of glucose into muscles so that in flight fright response it will help us ! ( this is from kaplan biochem there are two good pathways also in that book during well fed state pathway so u can correlate it ! Easy?
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Quote:
Originally Posted by yasirsattar75 View Post
I think it makes sense so glycolysis so more energy and also insulin stimulates GLUT4 formation ( late effects) and more entry of glucose into muscles so that in flight fright response it will help us ! ( this is from kaplan biochem there are two good pathways also in that book during well fed state pathway so u can correlate it ! Easy?
in well fed state increase insulin level thats correct but in postabsorptive state or starvation no role of insulin,its levels decreases..
i dont know whats concept behind b2 receptor activation:as we know during fight or flight or exercise (stress) epi:causes vasodilation,bronchodilation,gluconeogensis etc insulin has no any role in stress
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during stress, beta2 stimulation occurs, increases insulin release. we have to understand here that when there s gluconeogenesis and glycogenolysis there s elevated glucose levels,we need some insulin in order to drive glucose into the cells and make it available for energy production. Insulin s not a stress hormone.
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Quote:
Originally Posted by daulath singh View Post
during stress, beta2 stimulation occurs, increases insulin release. we have to understand here that when there s gluconeogenesis and glycogenolysis there s elevated glucose levels,we need some insulin in order to drive glucose into the cells and make it available for energy production. Insulin s not a stress hormone.
I think this one makes more sense!

As i said in the beginning, insulin secretion doesn't happen directly from activation of β2 receptors...
β2 agonists induce glycogenolysis in liver and muscle and gluconeogenesis in liver (epinephrine increases the release of endogenous stores of glucose)
So, because of the elevated glucose levels in liver and blood (biochemistry stuff, as most of you say...), insulin secretion from pancreas increases.
And THAT'S WHY we should be careful in diabetic patients and increase insulin dosage (with β aginists)!
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Old 12-15-2011
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Quote:
Originally Posted by daulath singh View Post
during stress, beta2 stimulation occurs, increases insulin release. we have to understand here that when there s gluconeogenesis and glycogenolysis there s elevated glucose levels,we need some insulin in order to drive glucose into the cells and make it available for energy production. Insulin s not a stress hormone.
yup insulin is not a stres hormone but mine question is b-cells on pancreas stimulated simultaneously with glcogenolysis in liver and skeletal muscle? you are saying that some insulin needed to drive glucose in cells for energy production you are right but i didnt read anywhere that during stress insulin is also released with stress hormones
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Old 12-16-2011
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Quote:
Originally Posted by riya_rai84 View Post
yup insulin is not a stres hormone but mine question is b-cells on pancreas stimulated simultaneously with glcogenolysis in liver and skeletal muscle? you are saying that some insulin needed to drive glucose in cells for energy production you are right but i didnt read anywhere that during stress insulin is also released with stress hormones
Ill try to clear this..during stress conditions, stress hormones are released 1.e., Growth hormone, cortisol, glucagon and epinephrine. Glucagon has amino acid sequence similar to duodenal hormone, secretin. hence like secretin and most other gut hormones glucagon increases insulin secretion. Its just to augment the uptake of glucose by cells, insulin secretion increases( but not to levels seen in postprandial states). i remem the physio teacher in kaplan videos saying this!!!
The first question- yes i feel they are stimulated simultaneously. Even epinephrine thru beta2 receptors increases insulin levels.
Bottomline: Its the stress hormones that increases insulin secretion
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Old 12-16-2011
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Glucose uptake in exercising muscles is independent of insulin.

However, during fasting insulin is required to push glucose in myocytes.
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