Theories abound as to why ferrets appear to be
prone to adrenal disease. If one were to scan the various discussions
on this topic on the Internet, one would find the blame placed on
a number of different causes. I've been involved in group discussions
in which adrenal problems have been attributed to early neutering,
Marshall Farms, environmental effects, inbreeding, or diet. There
is another possible cause that has piqued my interest over the last
year or so, and that is the effects of the abnormal lighting cycle
to which we subject our ferrets.
Can we cure our ferrets simply
by subjecting them to a more "normal" light cycle?
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The light cycle, or photoperiod, is the amount
of time a plant or animal is exposed to light in a 24 hour period.
This can be daylight, but it can also be artificial light to which
our ferrets are exposed by our desire to be able to see in our home
at night and not stumble over chairs, assorted ferret toys and even
our beloved ferrets. This is not an unreasonable desire, but it can
subject our ferrets to 16 or more hours of "daylight" almost every
day of the year.
In one issue of the "Ferret Adrenal/Insulinoma
Mailing List," an Internet discussion group, Cathy Johnson-Delaney,
DVM, speculated that adrenal disease may have some relation to the
pituitary-adrenal feedback. The pituitary gland gets turned on due
to a long photoperiod, and as a result, the adrenal is super stimulated
and becomes hyperplastic [abnormal multiplication of cells] and eventually,
neoplastic [a new growth of different or abnormal tissue, e.g. a tumor].
According to Dr. Johnson-Delaney, any tissue which is constantly stimulated
over a long period goes hyperplastic, and the more cell cycles and
stimulation, the greater the chance for neoplasia. This is particularly
true with secreting tissue, such as the adrenal gland.
Dr. Judy Bell, former veterinarian for Marshall
Farms, also theorizes that adrenal problems may be due to the abnormal
light cycles to which we subject our ferrets. Dr. Bell has proposed
testing light amounts and measurements of melatonin, and attempting
to keep one's ferrets on an eight hour light cycle.
In relation to melatonin, Jerry Murray, DVM, says
that melatonin directly and indirectly controls the hypothalamus-pituitary-adrenal/gonadal
axis. During the longer days of spring and summer, the level of melatonin
decreases and during the short days of fall and winter, levels increase.
These increases and decreases in melatonin levels
cause the seasonal weight increase and decrease, begins and ends the
estrus cycle and stimulates the hair follicles to grow hair or cause
it to shed.
So what does all this medical talk mean? Can we
cure our adrenal ferrets simply by subjecting them to a more "normal"
light cycle? Dr. Cathy Johnson-Delaney says, "... most people agree
that artificial light cycles can't cure adrenal disease once it's
begun."
Also, Jerry Murray, DVM, says that increasing melatonin
levels by using a short photoperiod will cause hair growth and weight
gain. In the short term, this may look good, but one is not actually
curing the ferret. As the photoperiod increases and melatonin levels
decrease, signs of estrus and hair loss will re-occur and become progressively
worse.
Dr. Murray says an artificially regulated photoperiod
is best used in the following instances: After adrenal surgery, when
surgery is too risky due to other health concerns, if the owner simply
cannot afford surgery, or when the left adrenal has already been removed
and the right adrenal has been debulked.
It is interesting to note that ferrets with adrenal
problems will often go into temporary remission without any treatment.
If you visited our shelter, you would have seen this in Flower, who
was totally naked due to adrenal problems. She had a few tufts of
hair on her head and on her legs, but was otherwise hairless. A short
time later, Flower had spontaneously re-grown all of her hair except
for a small spot near the base of her tail. She had received no treatment
that would account for this.
The point being, it's often hard to determine if
an experimental treatment is the reason for hair growth in ferrets,
or if it was simply spontaneous like we saw in Flower. It's not unusual
for ferret owners desperate for an answer to jump to conclusions by
the results achieved on a few ferrets given an experimental treatment.
So, are we once again jumping to conclusions in
hoping that a more natural lighting cycle is the answer? No one knows
at this point in time. It's a pretty sure bet that it's not a cure,
but a preventative measure at best. It seems that surgical removal
is still the best cure for a diseased adrenal gland. The good news
is that placing your ferrets in a more natural lighting environment
cannot possibly be harmful, and there's no great expense involved.
The biggest problem is the difficulty of keeping your ferrets in darkness
or very low light levels during the very times you want them to be
out and about with you.
© Copyright
Mike Janke All Rights
Reserved.
This article may be reproduced and freely reprinted provided no
modifications or changes are made and the author is credited. Not-for-profit
ferret organizations may distribute this article with their contact
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