Local insulin?

[Wallace]

Hi everyone!

I was just wondering about insulin and IGF1.
they are VERY similar in molecular structure AND mechanism of action. It is not a case that IGF1 means Insulin Like Growth Factor ...

IGF1 has been used, not only in the bb arena but in the medical fields as well, as a local anabolic agent in muscle tissue.

Has anyone tried insulin in the same way?

Intramuscular injection of insulin results in fast absorption and consequent lowering of blodd sugar (and all others insulin actions of course).
The same is supposed to happen with IGF1, yet it's been used locally ... with success ...

Wallace

 

[Mr_Magoo]

Hi everyone!

I was just wondering about insulin and IGF1.
they are VERY similar in molecular structure AND mechanism of action. It is not a case that IGF1 means Insulin Like Growth Factor ...

u mean IGF-1 does mean and stand for Insulin Like Growth Factor

 

[Wallace]

u mean IGF-1 does mean and stand for Insulin Like Growth Factor

Yes, I mean that

 

[The_Beast]

Insulin can bind either to insulin of IGF-1 receptors. So it stands to reason that local injections would activate local IGF-1 receptors and might promote localized growth.

Here's an interesting text on that topic:

"Both IGF-1 and insulin receptors have similar structural and functional characteristics. The IGF-1 receptor is a glycoprotein made up of two peripheral a subunits and two transmembrane b subunits with an intracellular tyrosine kinase domain. The insulin receptor is also transmembrane glycoprotein made of two a and two b subunits covalently attached by a disulfide bond (4). The similarity of the two receptors indicates that their ligands can bind to either one, but they do so typically in high concentrations. Just as the insulin receptor, the IGF-1 receptor is in the tyrosine kinase class of receptors, which includes a tyrosine kinase domain on the intracellular side of the membrane.

One study showed the binding of insulin did not use the insulin receptor to initiate its effects. It was found that when insulin wields it mitogenic effects on rat arterial endothelial cell, it does so using the IGF-1 receptor (4). An inhibitor of the IGF-1 receptor was used to show that insulin was binding to the IGF-1 receptor and not to the insulin receptor. The inhibition of the IGF-1 receptor caused the inhibition of the growth promoting effects of insulin. Although several studies have stated that IGF-1 can imitate particular metabolic actions of insulin, there has been debate as to whether the metabolic effects of IGF-1 are exerted through insulin or IGF-1 receptor or through insulin/IGF-1 hybrid receptors (5). Although there has been controversy on how both receptors are activated, most of the studies have generally indicated the use of insulin and IGF-1 receptors and not a hybrid receptor. So in general the receptors can be stimulated by either insulin or IGF-1."

 

[finephysique]

Insulin and IGF-1 taken together can be a scary combo, I tried it with 50mcg IGF and 5i.u of isulin and went hypo about 30 minutes later even though I adhered to proper insulin contolling protocols which I would use when taking 12i.u. of insulin