insulin-like growth factor

Ray Frackelton A_Frackelton_Jr at BROWN.EDU
Fri Sep 15 19:29:30 EST 1995



In article <GRAND%LISTS.BIOFORUM.14009 at brownvm.brown.edu>,
mkolotila at neccadm1.necc.mass.edu (Michael Kolotila x3887) wrote:

> Hi Bionetters;
> Does any have any information about insulin-like growth factor to
> increase muscle mass for body builders.  Is it effective or a load of b.s.?
> Thanks in advance.
> -Michael-
> 
> ******************************************************************************
>  Michael P. Kolotila, Ph.D.        * e-mail: mkolotila at neccadm1.necc.mass.edu
>                                    *
>  Biotechnology Program Coordinator *
>  Department of Natural Science     * voice :  508-374-3887
>  Northern Essex Community College  *
>  100 Elliott Way                   * fax   :  508-374-3723
>  Haverhill, MA  01830-2399         *
> ******************************************************************************

Insulin-like growth factor (IGF-1, also called somatomedin C) is normally
produced in the body in response, primarily, to growth hormone secreted
from the anterior pituitary.  IGF-1 seems to be the main effector for
growth hormone.  You may recall hearing about "pituitary
giants"...individuals who basically never stop growing due to a pituitary
tumor that constitutively secretes growth hormone (thereby elevating IGF-1
frequently by many fold).  However, growth hormone (or IGF-1) secreted (or
administered) after the bone epiphysis has closed, (late adolescence),
results in acral growth (acromegaly)...that is, fingers and feet become
very thick (custom shoes of EEEEEE width), spurs of bone develop typically
in the shoulders, along the vertebral column, etc., resulting in
osteoarthritis and a variety of nerve-entrapment syndromes (like carpal
tunnel syndrome, etc.). The lower jaw experiences acral growth where it
articulates with the skull, resulting in a pronounced protrusion of up to
several millimeters.  The facial skin becomes jowel-like, and the tongue
and lips frequently grow so thick as to impede normal speech.  Patients
are intolerant of heat, and frequently present clinically with back pain,
nerve entrapments, recurring headaches (enlarged sinuses), osteoarthritis
and heart palpitations.   Systemically, hypertrophy of the heart, lungs
and other organs occurs.  

In short, although IGF-1, like growth hormone, might increase muscle mass
a bit (although it generally leads to muscle weakness), it should not be
used for that purpose.  The only indication I can think of is to increase
the height of "stunted" children.  In people who have no pituitary
function (due to surgical removal or infarction) there might be an
argument for restoring growth hormone and/or IGF-1 to normal levels, but a
clear case has not yet been made to my knowledge.

-- 
Ray Frackelton
Ph/Fax 456-2320
EMail A_Frackelton_Jr at brown.edu



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