Does igf-1 bind to insulin receptors

**Marcus G** · 02-16-2017, 01:44 PM

My question is if using igf-1 with insulin together will desensitise insulin receptors quicker than just insulin alone?

**Marsoc** · 02-16-2017, 01:50 PM

has anyone heard of Mecaserim...is that a supplement for long term treatment to growth failure in children..can this be effective

**DocToxin8** · 02-16-2017, 02:01 PM

Originally Posted by Marcus G

My question is if using igf-1 with insulin together will desensitise insulin receptors quicker than just insulin alone?

Can't see why it would.
But igf1 lowers blood sugar through other mechanisms I believe,
and I also believe that low blood sugar leads to reduced insulin sensitivity.

But IGF-1 and insulin has very low affinity for each other's receptors.
I'll see if I can dig up some info on this.

**Marcus G** · 02-16-2017, 02:23 PM

Originally Posted by DocToxin8

Can't see why it would.
But igf1 lowers blood sugar through other mechanisms I believe,
and I also believe that low blood sugar leads to reduced insulin sensitivity.

But IGF-1 and insulin has very low affinity for each other's receptors.
I'll see if I can dig up some info on this.

I appreciate your response, the reason I ask is because I'm sure I've read it somewhat that it effects the insulin receptor to a degree however I cannot seam to find much info on it.

**DocToxin8** · 02-16-2017, 03:47 PM

Well,with studies were they've used 100x the normal concentration of insulin it has also bound to IGF-1 receptors, but I doubt it happens in vivo.
Other than that I also think IGF1 influence IR (insulin receptor signaling),
but I have to read up on that. If anything i think it increased IR sensitivity.
HGH on the other had decrease IR sensitivity. (That I'm sure of)

**Marcus G** · 02-16-2017, 05:29 PM

Thanks for the your input Yh I know about Hgh effecting IR and rising bd (blood sugar) that's why I run low does of slin 1-2ius when ever I run Hgh

**smm9999** · 02-16-2017, 10:39 PM

There's lots to digest in this study..
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300772/

"they (referenced studies) suggest that the major site at which GH blocks insulin action is the liver. Although a secondary role for GH in skeletal muscle cannot be excluded, by this formulation, conditions that lead to increases in GH secretion (whether or not they are associated with lower serum IGF-1) may result in impaired hepatic insulin sensitivity, leading to decreased suppression of gluconeogenesis"]hey suggest that the major site at which GH blocks insulin action is the liver. Although a secondary role for GH in skeletal muscle cannot be excluded, by this formulation, conditions that lead to increases in GH secretion (whether or not they are associated with lower serum IGF-1) may result in impaired hepatic insulin sensitivity, leading to decreased "suppression of gluconeogenesis"

Another take home point is that insulin sensitivity/resistance is not systemic.. it's tissue specific.

**Marcus G** · 02-17-2017, 04:10 AM

Originally Posted by smm9999

There's lots to digest in this study..
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC300772/

"they (referenced studies) suggest that the major site at which GH blocks insulin action is the liver. Although a secondary role for GH in skeletal muscle cannot be excluded, by this formulation, conditions that lead to increases in GH secretion (whether or not they are associated with lower serum IGF-1) may result in impaired hepatic insulin sensitivity, leading to decreased suppression of gluconeogenesis"]hey suggest that the major site at which GH blocks insulin action is the liver. Although a secondary role for GH in skeletal muscle cannot be excluded, by this formulation, conditions that lead to increases in GH secretion (whether or not they are associated with lower serum IGF-1) may result in impaired hepatic insulin sensitivity, leading to decreased "suppression of gluconeogenesis"

Another take home point is that insulin sensitivity/resistance is not systemic.. it's tissue specific.

Great info I appreciate it, yh I'm well aware of how gh effects insulin but what I'm struggling with is if igf-1 (synthetic) has an effect on desensitising insulin receptors..

**smm9999** · 02-17-2017, 05:34 AM

Oh, got it. I was misreading your post and replacing IGF-1 with GH in my head.

This section of the study/article seems to be a little more on target...
"IGF-1 binds to insulin receptors with very low affinity; therefore its binding to IGF-1 receptors and/or hybrid insulin/IGF-1 receptors has been postulated to be the mediator of enhanced insulin action (12). IGF-1 does not bind to hepatocytes or adipocytes, and therefore its primary insulin-sensitizing action is believed to be mediated through skeletal muscle. Administration of IGF-1 to normal humans results in glucose lowering that is approximately one-twelfth as potent as that induced by insulin (13), and in patients with extreme insulin resistance it improves insulin sensitivity and carbohydrate homeostasis (14)."

However, the next paragraph is complicates this statement because IGF-1 also suppresses GH secretion...
"One problem in interpreting almost all human studies of IGF-1 has been that, in addition to enhancing insulin action, it also suppresses GH secretion; therefore it has been difficult to determine the relative roles of the direct actions of IGF-1 and those that are mediated by suppression of GH."