Now then…what about IGF-1 and hair growth/hair loss?
I called several doctors in town, and since I wasn’t their patient,
they wouldn’t discuss the issue even in hypothetical terms (poor
fellas have liability and malpractice issues to worry about, I really
can’t blame them for being reluctant).
My next step was to call my own physician and ask for a few minutes.
I quizzed him briefly on the uses of IGF-1, and he basically confirmed
the functions noted above. When the discussion moved to hair
loss/hair growth, he said that there wasn’t much research in that
area, and that he wasn’t very familiar with the research that was out
there. Not much help, but understandable. He’s a GP, and doesn’t
oversee hormone treatments – he sends patients off to the
endocrinologists for that.
He suggested that you make an appointment with your own physician to
discuss your concerns, preferably the one overseeing your use of
IGF-1, because s/he’ll be more familiar with your situation and your
specific needs.
My next step was to try to gather general information on the subject.
Researcher kevinmd pointed me to the following excellent answer he
wrote for you as a starting point in my investigations:
Growth hormone
http://answers.google.com/answers/main? ... &id=157723
In his answer, our Dr. Kevin notes that with respect to whether IGF-1
stimulates hair growth or promotes hair loss, there is no real
consensus. He cites the following two studies, one which points to
growth, one which points to loss:
Su HY, Hickford JG, Bickerstaffe R, Palmer BR. Insulin-like growth
factor 1 and hair growth. Dermatol Online J. 1999 Nov;5(2):1.
Signorello LB, Wuu J, Hsieh C, Tzonou A, Trichopoulos D, Mantzoros CS.
Hormones and hair patterning in men: a role for insulin-like growth
factor 1? J Am Acad Dermatol. 1999 Feb;40(2 Pt 1):200-3.
My next step was to contact my friend Jeff, an MD/PhD student at the
University of Michigan Medical School. Jeff’s main focus is cancer
research, so considering the attention growth hormones have been given
in conjunction with cancer, he seemed like the guy to ask.
In his response to me, Jeff noted:
“To: Maggie <maggie_sedai>
Subject: Re: Need Guidance!
On Wed, 12 Mar 2003, Maggie wrote:
> I have a customer who wants to know about IGF-1 and hair growth -
> specifically, if your IGF-1 level increases, do you grow more hair,
> and if it decreases, do you lose more? Or vice versa?
>
> Do you know any good articles I could read on the subject?
I've pulled two off of the U. Mich. library system and copied them to
my home directory, with the punchlines highlighted in red:
http://www.umich.edu [elided for Jeff’s privacy ]
http://www.umich.edu [elided for Jeff’s privacy ]
At first glance, answer seems to be there's not a whole lot of
research, but what there is suggests increased IGF-1 might possibly be
connected to vertex balding.â€
He went on to note that though research appeared sparse, there were
other avenues to try, and directed me to several other resources.
Though they were helpful in terms of confirming that research is
sparse and conflicting, I’m afraid they didn’t do much to
definitively answer that portion of your query.
Here are excerpts from the articles Jeff provided:
Occurrence of the male hair pattern is considered to be an
androgen-mediated process that depends on circulating testosterone and
dihydrotestosterone concentrations as well as on local conversion of
circulating testosterone to dihydrotestosterone in the skin (catalyzed
by the enzyme 5alpha-reductase). Our data confirm that there is a
stronger link between circulating testosterone and baldness, whereas
testosterone has a less obvious function in regulating the relatively
less androgen-dependent chest hair density. Androgen action stimulates
vellus hair to develop into coarse, pigmented hair on the body, but
prolonged exposure to androgen leads to regression to vellus hair and,
frequently, balding of the scalp. Little is known about the specific
function of SHBG or estradiol in male hair growth or hair loss, and
the results of our study, in this respect, must be replicated before a
credible conclusion can be reached. It is conceivable, however, that
high SHBG levels reduce the bioavailability of testosterone and thus
modulate its effect on hair patterning.
Our findings suggest that high levels of IGF-1 may be associated with
increased risk of vertex baldness. Substantial clinical evidence
appears to support this finding. The efficacy of testosterone
treatment on hair growth in children with hypopituitarism is enhanced
by GH, the effect of which is largely mediated through IGF-1. In
adults with hypogonadism, a combination of GH and gonadotropin
treatment improves testosterone secretion and reproductive function.
It has also been recently reported that GH treatment of GH-deficient
men increases hair scores in androgen-dependent areas. These effects
can be explained either by IGF-1 directly stimulating the androgen
receptor, or by IGF-1 increasing local 5alpha-reductase activity and
thus stimulating the local conversion of testosterone to
dihydrotestosterone. It has been postulated that IGF-1 modifies
post-receptor effectors of the androgen receptor, but this is not
clearly established.
[…]
In conclusion, we have found evidence that high levels of testosterone
and IGF-1 increase the likelihood of vertex baldness, whereas neither
of these hormones appears significantly or suggestively associated
with chest hair growth. SHBG is inversely associated with vertex
baldness as well as with chest hair growth, although the association
is significant only with respect to the latter. It appears that the
effect of SHBG, if genuine, could be explained by the involvement of
this compound in the modulation of bioavailability of testosterone.â€
Hormones and hair patterning in men: A role for insulin-like growth
factor 1?
Lisa B. Signorello, Joanne Wuub, Chung-cheng Hsiehb, Anastasia
Tzonouc, Dimitrios Trichopoulos, Christos S. Mantzoros
Journal of the American Academy of Dermatology
Volume 40 • Number 2 • February 1999
Copyright © 1999 American Academy of Dermatology, Inc.
“We observed that middle-aged and elderly men who reported modest to
substantial vertex balding at age 45 have lower circulating levels of
IGFBP-3 and higher levels of IGF-1 when controlling for IGFBP-3 level.
Growth factors are beginning to emerge as contributors to hair growth
and loss. IGF-1 is an abundant endocrine, paracrine, and autocrine
growth control factor that promotes proliferative activity in
epithelial and mesenchymal cells in numerous organ systems, including
the hair organ.â€
[…]
“In the hair organ, IGF-1 is produced by connective tissue
constituents,10 and IGF-1 gene expression is enhanced by androgens.11
In androgen-responsive tissue, IGF-1 may act locally to positively
mediate the induction of 5-reductase by dihydrotestosterone.12 This
action of IGF-1 may be consequential for the development of balding
because conversion of testosterone to dihydrotestosterone in the scalp
by 5-reductase type 2 is essential for androgenetic alopecia.13
Indeed, oral 5-reductase type 2 inhibitors are now used to prevent
further hair loss and to induce hair regrowth in men with male pattern
balding.13 Experimental administration of the 5-reductase type 2
inhibitor finasteride results in diminished expression of IGF-1 and
its receptor and enhanced expression of IGFBP-3 in the rat prostate,
an androgen-dependent tissue.14 IGFBP-3 is the major carrier protein
that modulates the bioavailability of IGF-115 and thus may also be a
regulator of mediators of hair growth and cycle control. Our findings
are compatible with both the direct association of IGF-1 and the
modulating effect of IGFBP-3 on male pattern balding.â€
[…]
“Misclassification of hair loss is possible because of self-assessment
of hair pattern up to 36 years in the past. However, there was little
correlation (r = 0.04) between age at blood draw (approximately 2
years after self-report on hair pattern) and balding at age 45,
suggesting that systematic underestimation or overestimation of the
extent of vertex balding by elderly compared with middle-aged
participants was not extensive.
The association between IGF-1 and vertex balding was only evident in
our study after adjusting for IGFBP-3, and the magnitude of the
association for IGF-1 adjusted for IGFBP-3 was not as great as shown
for IGF-1 by Signorello et al.2 Differences in the two studies that
might contribute to the disparity in the strength of the association
between IGF-1 and vertex balding include different IGF-1 assays, older
average age in the Greek study, interviewer-assessed balding in the
Greek study versus self-report in our study, and IGF-1 and balding
assessed concurrently in the Greek study versus 2 to 36 years apart in
our study. In the Greek study, adjustment for sex hormones and sex
hormone-binding globulin enhanced the risk of vertex balding
associated with IGF-1. Although not presented here because of possible
noncomparability of hormone data among the 3 samples that we included
in this analysis, adjustment for sex steroids and sex hormone-binding
globulin did not appear to alter our estimates for the relation of
vertex balding with IGF-1 or IGFBP-3. Despite these methodologic and
population differences between the two studies, both the study in
elderly Greek men2 and our study indicate that the IGF-1 axis may be
important in male pattern hair loss.â€
Vertex balding, plasma insulin-like growth factor 1, and insulin-like
growth factor binding protein 3
Elizabeth A. Platz, ScD , Michael N. Pollak, MD , Walter C. Willett,
MD, DrPH, Edward Giovannucci, MD, ScD
Boston, Massachusetts, and Montreal, Canada
Journal of the American Academy of Dermatology
June 2000 • Volume 42 • Number 6
Copyright © 2000 by the American Academy of Dermatology, Inc.
The short of it? They don’t really know yet. The matter is still
under study.
Hrm.
http://answers.google.com/answers/threadview?id=175072
