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pls forgive me for posting what may seem to u a rather trivial thread. I need some clarification.

Among beta-blocker (Propranolol) side effects is hyperlipidemia, hypoglycemia, hypotension, sedation, bradycardia n bronchoconstriction.
The part I don't quite get is that beta2 agonists causes increase in insulin secretion, but beta blockers cause hypoglycemia? is it because the fact that beta blockers also cause an increase in glucose that the increase in glucose overrides the insulin increase, that when u block beta receptors, the fall in glucose (causing hypoglycemia) is more prominent than the fall in insulin levels (which may cause hyperglycemia, but evidently does NOT in case of Propranolol)????:eek:

What is it that I'm missing here?
 

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I think it's the fact that beta2 receptors are found on the hepatocytes and stimuate glycogenolysis and gluconeogensis which maintain blood glucose levels in between meals; further more beta2 receptors are also found on the alpha cells and stimulate the release of glucagon.
Both of these actions are inhibited by beta blockers.

I think that is why you are likely to see hypoglycemia with propranolol.
 

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I think Inder is right. - Hypoglycemia can occur with beta-blockade because β2-adrenoceptors normally stimulate hepatic glycogen breakdown (glycogenolysis) and pancreatic release of glucagon, which work together to increase plasma glucose. Therefore, blocking β2-adrenoceptors lowers plasma glucose.

A very important point, however, is that Beta blockers are "use with caution" in diabetics because they block the normal symptoms of hypoglycemia. Diabetics get tremors when they're becoming hypoglycemic and beta blockers can block any warning till their blood sugar is so low they show neurological symptoms and now the brain has been without glucose for some time...

β1specific blockers have fewer metabolic side effects in diabetic patient (β2 receptors on the liver and pancreas) but since they also block the heart there might be fewer symptoms of hypoglycemia so they should be used carefully too.
 

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Beta blockers disrupt the levels of glucose but we cannot generalize that they cause hypoglycemia because evidence based information in therapeutic choices states that they cause hyperglycemia ...they also mask the hypoglycemic effect of antihyperglycemic drugs but thats because of effect on autonomic nervous system mimicking hypoglycemia signs ... anyways individual agents behave differently ... eventhough inhibition of glycogenolysis sounds logical... and i can only think b2 receptors stimulation causes release of insulin and blockade would probably decrease insulin leading to hyperglycmeia....
 

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infact seetal rightly pointed out what i was thinking about that decreased insulin production would lead to hyperglycemia ... i m not sure about this ... so thats why i think they can cause both i said ... so better of assume they dirupt the glucose levels but propranolol for sure causes hypoglycemia thats also confirmed:)
 
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