IGF-1 =
insulin-like
growth hormone
To start with the
advertising claims, here's what this
wonderful supplement
may do to your
body:
http://www.igf-1plus.com/ (they do have a
cool 3D structure of the
molecule :) ) states 23
beneficiary effects, ranging from sharpened
mental alertness to reduced
inflammation & decreased
pain in
arthritis and correction of
impotence. It is also said to combat several
deseases and the perfect
substance for "gaining
muscle and
losing
fat". In other words, yet another
drug on thee list of
ultimate
fantastic wonder treatment.
My information is that IGF-1 supplements are produced by genetically
modified micro-organisms (for bulk production), but it's also possible to
induce production in the liver.
Yeah, right!
Call me
skeptical if you want, but after a certain dose of
human
physiology lectures at
university and spending a couple of years in
the
medical circuit as a
patient myself, I've lost any little bit of
faith in such
claims. So, what do the
researchers themselves say about IGF-1
? My main source for the information written below is the
"
Growth Hormone & IGF Research"
scientific magazine (readable online at
http://www.harcourt-international.com/journals/ghir/default.cfm)
Function
Insulin-like growth factors (IGFs) are produced in the
brain and
participate in
brain development via activation of the type 1 IGF
receptor. IGF binding proteins (IGFBP-1)
modulate the
cellular action
of IGFs and some are expressed in the
fetal brain. IGF tests can be used in
the
diagnosis of GH
hypersecretion or
hyposecretion (i.e. too much or
insufficient production). Further, there are indications that there's a role
for IGF-I measurement as an
index of
nitrogen balance and in monitoring
remission of
breast cancer under treatment with and
oestrogen receptor
antagonist. (how? why?)
This for what it affects, but the interesting part of course is: what happens
if you have too much of it, or insufficient levels?
Research results
In accordance with the
common practice in the
pharmaceutical area,
animal tests with
transgenic mice and rats are being carried out.
First, the IGFBP-1 overproduction in mice
fetuses: effects include
reproductive defects, ante- and perinatal
mortality and
post-natal
growth
retardation and there were some cases of head enlargement. The width
of the
cerebral cortex was reduced in
homozygotes (the transgene mice,
not the
control group), with disorganized
neuronal layers. Similar
anomalies have been reported in mice with
disruption of the IGF-1 gene and
in a model of transgenic mice over-expressing IGFBP-1 in all
tissues,
including the brain. Conclusion: the results indicate that (at least)
hepatic over-expression of IGFBP-1 may have
endocrine effects on
brain
development. This makes me wonder if
pregnant women taking the IGF-1 drug
expose their fetus to these threats. Browsing through the magazine's
database, there was no
report that mentioned if they tested this
hypothesis
on animals.
Secondly, the previously mentioned
weight loss. Weight change was positively
correlated with
serum free IGF-I, but not with total IGF-I. It is
proposed that in rats the (
glucocorticoid-induced) weight loss may in part
be due to
suppression of circulating free IGF-I.
Third,
deficiency in IGF-1 is related to
infertility, delayed
bone
development, retarded
post-natal growth, reduced adult weight and growth
deficiency (http://www.bioscience.org/knockout/igf-1.htm).
Ok, ok, I made a
selection of the
research results I've illustrated here,
but there certainly wasn't
scientific back-up of the mentioned claims in
the ads. Further, by no means you can ever say that when you have the
situation of a
deficiency + IGF-
treatment (or any
drug treatment) up to
normal levels (which is
beneficiary), the same postive
correlation may be
measured when going from normal levels up to an
overdose!!
See also
human growth hormone by
factgirl