This is from Judi Bell, the ferret specialist vet, with some of her ideas
on possible relationships to adrenal growths.  It fits in well with the
darkness studies which were mentioned recently in the FML.  (Those basically
have been cutting edge studies (a hefty number of them) into the importance
of not disrupting the melatonin cycles for both the incidence reduction of
some types of cancers, and for reducing the rate of growth.  It appears
that there is a dark side to too much light.  One thing that may need to
be known (just my feeling from the human studies for which 2 to 3 a.m. is
usually peak production time) might be when the typical largest melatonin
output happens in ferrets on natural light with short days -- that would
allow work to be done to find WHEN melatonin could be given to the ferrets
orally to allow peak amounts in the body at about the same time that peaks
would happen naturally; I say this because such an emphasis is make on the
DISRUPTION of the cycle as well as the depletion in melatonin amounts being
possible culprits.)
 
Unfortunately, many of us (including us) don't have ANY way to provide
COMPLETE darkness for 14 hours each day, though we can reduce light with
boxes and such.  I think I should find a way to get wooden boxes the right
size that I can work up "black-out curtains" and wraps for (We'd need them
to not be at risk of asphyxiation.  If anyone on the FML has seen things
like that or ready made ones that would modify well, we'd sure like to
know about them!  Is anyone out there a carpenter with an interest in
introducing a new ferret product line: an assortment of hanging and
non-hanging darkness sleeping boxes in a range of sizes, complete with
blackout curtains over the holes so there's enough air exchange but also
light is excluded?  Hey, I'd take 4 to 6 of them for giving you the idea
if you are after a profit <G> and would buy if they help a shelter!
 -----
 
Sukie:
I wanted to make sure you got the story straight, instead of second or
third hand, which often loses a little with each translation.
 
First, I've believed for several years that the reason North American
ferrets get adrenal gland problems is because of their unnatural exposure
to long hours of light (long photoperiods) all year round.  I've been
saying this at every opportunity since 1995.  I presented it as a case at
the ferret veterinary meeting at the veterinary school in Madison in June,
1996, and suggested that injectable melatonin might cause some miraculous
recoveries, as might oral melatonin, but I'd never tried it.  I've owned
about 20 ferrets that lived in my house, and until this year, never had one
that showed signs of adrenal gland impairment, so I didn't have one to test
the theory on.  I attribute the lack of adrenal gland problems to the fact
that I always kept the ferrets in their own room, and let them have natural
light only.  A lady in the audience had some experience with melatonin, and
said it probably would have to be given late afternoon, when you wanted
"the sun to go down" (my expression) to be effective.
 
I've continued to suggest putting a hairless ferret in total, complete,
utter blackness for 14 hours a day, but until recently, I think no one took
my advice, or they didn't let me know if they did.  Recently, I took my own
advice.
 
Last winter, my 6 ferrets lived in a partly finished room in the basement
of the townhouse I rented here in Guelph.  Their cages were in the
basement, but they stayed upstairs with me from mid-afternoon until 10 or
so at night.  I noticed that they didn't grow very good winter coats, and
one day in January, went down very early in the morning and found that a
lot of light was getting to them through their window, which had an eastern
exposure.  So they were getting a lot more hours of pretty strong light
than I thought.  I covered the window so that not a ray of light got in,
and continued with their usual schedule.  Five of them grew pretty good
coats although it was late in the season, but one ferret went on to lose
most of her hair during the summer.  This was Ruan, a jill that is probably
5 years old this year.  She gradually lost all her hair, and had a slight
vulvar swelling.  Of course I could have taken a guess at the dose, but I
moved to a condominium in July, and it's been one of those falls where I
never seemed to be able to get caught up to myself.  So instead, when I
went to England, I instructed the house-sitter ... to leave the lights off
when he wasn't there.  They were then on completely natural light, and not
much of it, because they still live in a basement room.  When I returned,
about 2 weeks later, Ruan was as bald as ever, but in another 2 weeks, the
vulvar swelling disappeared, and new hair began to grow around her neck and
front legs.  That was a week ago.  Today, she has fine hair all over her
body, and a reasonable if tufty coat at the front end.  I was unable to
palpate a tumour in her, so I was reasonably sure she didn't have a large
one, and I now suspect that she had hypertrophy alone.  I wouldn't doubt
you could cure all hairless ferrets that have hypertrophy alone by using a
strict winter photoperiod.  If you were less strict than I was, it would
probably still work, but less quickly.  The amount of light is important,
but the quality of light is also important.
 
At 1995 at Marshall Farms, I had 400 jills in a research order for a year,
that I was supposed to monitor for estrus.  They were put in a new building,
out of the way of the breeders and the male research ferrets, and in that
building there were only just-weaned males and females.  Once a day, a
technician came in to add more juveniles or take some away.  She had nothing
to do with my jills, and I had no idea when she was coming in.  However,
what happened was classic.  One half of my jills were in the row of cages
against the wall: there are light panels at the top of the wall, about 10
feet above the cages.  The other row was opposite the first, so that these
jills received more natural light than the ones in the cages under the
light panels.  Later we measured this with a light meter, and there was a
lot more light getting to the cages away from the wall.
 
I expected all the jills to come in heat at 4 1/2 to 5 months, the way
Marshall Farms' jills always do if you put them in long light cycles.
These were in a building with a timer, so that there should have been 16
hours of light daily.  But my jills didn't come in heat even after they
were 5 months old.  I couldn't figure out what was going on; the lights
were always on when I was checking them.  Then they began to come in heat:
this was about March, when they were 6 months old.  My first clue was that
the jills in the cages under the light panels were not coming in heat to
any extent, but about 1/2 of the ones opposite them were.  And then I
discovered the reason.  The technician was turning off the lights if she
came in late in the afternoon, over-riding the timer.  Why I don't know,
those technicians never turned anything off without being told and told
and told, and sometimes not then.  However, she was doing it.  So the jills
came in heat on the basis of the natural light alone.  Even though the tech
didn't turn the lights off every day, the difference it made was dramatic.
We put a special timer in that building that would take an act of congress
to over-ride.  The tech could no longer turn off the lights, and the
mystery was solved.  As soon as the lights were left on, all 400 jills
started coming in heat.
 
This confirms the extreme sensitivity of the ferret to light cycles per se,
and quality of light as well.  The building was not really dark even with
the lights off during the day, but only the jills that got enough natural
light on top of the irregular artificial lights responded.  This has been
tested over and over a long time ago, but people tend to dismiss that kind
of research as unimportant in this high-tech age.  Preventing adrenal gland
neoplasia may be as simple as turning off a light switch.  However, it is
very difficult to convince people that dark means completely, pitch-black
dark.  Covering the cage in a lighted room won't work, and having a little
light coming in the window won't work, if you're also going to let the
ferret stay in the house with the lights on all evening.  It has to be dark
enough that you can't see your hand before your face for at least 14 hours
a day, and more is better.  That doesn't mean you can't play with the
ferret in the evening; it means you have to modify your house so that the
ferret gets no light at all in the morning, and a maximum of 10 hours of
light in 24.
 
You can print any of this you like.  I'm taking pictures of my little Ruan,
hopefully some of the really bald ones will come out.  Tomorrow I'll take
some where you can see the fine growth of hair all over her.  Last week,
her whole hind end was still smooth and shiny.
[Posted in FML issue 2507]