Hi!
 
Some people were discussing some REALLY big ferrets from Canada, and someone
wondered how big the ferret would be had it not been castrated.  Well, I
just can't resist commenting.
 
Testosterone has a profound effect on bone growth.  It causes bones to grow
in thickness and in length, stimulating osteoblasts (cells that lay down new
bone) and calcium deposition.  Now you're probably thinking the intact male
would be HUGE.  Right?  Well, not exactly.  Testosterone also causes the
epiphyses (growth plates) of the long bones to fuse.  Once the epiphyses are
fused, the bones don't grow in length anymore.  In fact, males castrated
before puberty tend to be larger than intact males (or males castrated after
puberty).  Of course, castrated animals don't continue to grow forever, so
there are probably other factors involved as well.
 
BTW, estrogens have the same effect as far as causing rapid growth of bone
and closure of the epiphyses.  Though, I think estrogens stimulate
osteoclasts (cells that remove bone).
 
Pretty neat stuff!  Perhaps some bone experts out there would like to add
to/ correct any errors, etc. as I was writing this off the top of my head :)
 
                           Lisa, Daisy and Squirt
[Posted in FML issue 1634]