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IGF Cancer Theory

KBD

KBD

I Look Good...
Sep 13, 2010
2,312
107
#1
Recombinant human insulin-like growth factor I (IGF-I): risks and benefits of normalizing blood IGF-I concentrations.Clark RG.

Tercica, Inc., San Francisco, CA 94080-7111, USA.

Recombinant human (rh) insulin-like growth factor I (IGF-I) is being developed as a therapy for short stature caused by IGF deficiency (IGFD) and also for diabetes mellitus. To complement the human efficacy and safety data, a large amount of information is available regarding the pharmacology and toxicology of rhIGF-I in animals. This review summarizes the risks and benefits of normalizing blood IGF-I concentrations in IGFD, especially with regard to carcinogenicity, and compares and contrasts safety data for rhIGF-I, recombinant human growth hormone (rhGH),and insulin. A major difference between rhIGF-I and rhGH is that rhIGF-I (like insulin) has hypoglycaemic activity, whereas rhGH opposes insulin action and is diabetogenic. In most of their actions, GH - growth hormone (somatropin) - and IGF-I are similar. IGF-I mediates most of the actions of GH, so the safety of rhGH and that of rhIGF-I also share many common features. In animals, the transgenic expression of human growth hormone - somatropin - has been shown to act directly, by activating the prolactin receptor, to increase the incidence of mammary and prostate tumours. In comparison, the over-expression of IGF-I in animals or the administration of rhIGF-I does not have a carcinogenic effect. In formal toxicology and carcinogenicity studies, rhIGF-I has similar effects to insulin in that it can increase food intake, body size, and the growth rate of existing tumours. In animals and humans, IGFD has many long-term detrimental effects besides short stature: it increases the risk of diabetes, cardiovascular disease, and low bone mineral density. Therefore, a case can be made for replacement therapy with rhIGF-I to normalize blood IGF-I levels and reverse the detrimental effects of IGFD. Copyright 2004 S. Karger AG, Basel.

Recombinant rat and mouse growth hormones: risk assessment of carcinogenic potential in 2-year bioassays in rats and mice.

Farris GM, Miller GK, Wollenberg GK, Molon-Noblot S, Chan C, Prahalada S.
Department of Safety Assessment, Merck Research Laboratories, West Point, PA 19486, USA.

Recombinant rat growth hormone (rrGH) and recombinant mouse growth hormone (rmGH) were developed to evaluate the potential carcinogenicity of each biologically active growth hormone (GH - growth hormone (somatropin) - ) as assessed in the respective species. Biological activities of rrGH and rmGH were demonstrated by showing an increase in body weight gain and serum levels of insulin-like growth factor-1 (IGF-1) in hypophysectomized rats receiving daily sc injections for 6 days. With the exception of pharmacologically mediated weight gain, rrGH and rmGH had no adverse effects in 5-week oral toxicity studies and no production of anti-recombinant GH antibodies. The high doses selected for the carcinogenicity studies provided systemic exposures of GH up to approximately 10-fold over basal levels. In the 105-week mouse carcinogenicity study, daily sc injections of rmGH at 0.1, 0.2, or 0.5 mg/kg/day were well tolerated and had no effects on survival or incidence of tumors. In the 106-week rat carcinogenicity study, daily sc injections of rrGH at 0.2, 0.4, or 0.8 mg/kg/day had a favorable effect on longevity in female rats administered 0.4 or 0.8 mg/kg/day, an increased weight gain in females and males, and no increase in the incidence of tumors. The absence of carcinogenic effects of recombinant GH administered daily for 2 years to rodents was consistent with publications of clinical experience, indicating a lack of convincing evidence for an increased risk of cancer in children receiving human recombinant GH replacement therapy.
 
barbellbeast

barbellbeast

MuscleHead
Oct 4, 2010
343
43
#2
So the study show IGF-1 is not a carcinogen, but does that mean it also doesn't multiply cells that are already cancerous?
 
FlyingDragon

FlyingDragon

VIP Member
Nov 4, 2010
3,368
1,574
#3
In science, it is very rare for rodents and humans to have the same results. So many compounds work well in animals yet can rarely get duplicated when given to humans. I mean do you really want to rely on the data from a rat study when contemplating taking a specific compound? I would hope not!
 
ajdos

ajdos

MuscleHead
Sep 8, 2010
2,282
388
#4
I would be careful about that, anything that can cause growth of new cells can instigate oncogenes growing out of control.
 
KBD

KBD

I Look Good...
Sep 13, 2010
2,312
107
#5
So the study show IGF-1 is not a carcinogen, but does that mean it also doesn't multiply cells that are already cancerous?
Correct, from what the study says, it cannot cause cancer. However, if you already have cancer, im sure IGF-1 or HGH would accelerate the rate of spread.
 
JackD

JackD

Senior Moderators
Staff Member
Sep 16, 2010
5,066
538
#8
Don't ever allow animals studies to determine your stance on a topic, that is not a good indicator of what it will do inside of a human.

Humans are exposed to a lot more cancerous compounds than lab rats would be, thus increasing the effect that any rapid tissue growth can lead to cancerous cells being missed by the immune system increasing your risk of developing cancer of a specific tissue. Also, if your immune system is weak, or you have any immune disorder, this will also increase your risk of developing cancer, well that is if you don't die from some other disease or infection.
 
KBD

KBD

I Look Good...
Sep 13, 2010
2,312
107
#9
Don't ever allow animals studies to determine your stance on a topic, that is not a good indicator of what it will do inside of a human.

Humans are exposed to a lot more cancerous compounds than lab rats would be, thus increasing the effect that any rapid tissue growth can lead to cancerous cells being missed by the immune system increasing your risk of developing cancer of a specific tissue. Also, if your immune system is weak, or you have any immune disorder, this will also increase your risk of developing cancer, well that is if you don't die from some other disease or infection.
Im not using this as my guide. However, pro BBers have used large doses of IGF-1 and GH and i dont recall hearing that they have cancer.
 
ajdos

ajdos

MuscleHead
Sep 8, 2010
2,282
388
#10
Im not using this as my guide. However, pro BBers have used large doses of IGF-1 and GH and i dont recall hearing that they have cancer.
As with skin cancer due to exposure to the sun the cancer usually manifests itself long after the precursing event, in skin cancers case up to decades after...so long term studies are really needed for this to be at all more acurate and with pro bbers the word 'yet' comes to mind.
 
JackD

JackD

Senior Moderators
Staff Member
Sep 16, 2010
5,066
538
#11
As AJ said, the word yet has to be determined. I BB that I knew of back in the 90's I found out has pancreas issues, not sure if it's cancer, or it's just not working correctly, I didn't get into it, but I also know this guy has heart problems too. The key is to keep things simple and not go crazy with any of these compounds.

Im not using this as my guide. However, pro BBers have used large doses of IGF-1 and GH and i dont recall hearing that they have cancer.
As with skin cancer due to exposure to the sun the cancer usually manifests itself long after the precursing event, in skin cancers case up to decades after...so long term studies are really needed for this to be at all more acurate and with pro bbers the word 'yet' comes to mind.
 
KBD

KBD

I Look Good...
Sep 13, 2010
2,312
107
#12
As AJ said, the word yet has to be determined. I BB that I knew of back in the 90's I found out has pancreas issues, not sure if it's cancer, or it's just not working correctly, I didn't get into it, but I also know this guy has heart problems too. The key is to keep things simple and not go crazy with any of these compounds.

Insulin use?
 
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