From:
"Sukie Crandall"
Date: 2007-12-17 16:44:26 UTC
Subject: [ferrethealth] Re: Question on timing of light cycle
To: ferrethealth@yahoogroups.com
I actually know a ferret vet in another nation who always keeps her ferrets in a very dimly
lit room and darkness at night. Hers tend to have long and healthy lives.
We don't have that option, and I don't know if we would go that far, just from human
convenience. What is usually advised is access to 14 or more hours hours of complete
darkness -- i.e. WINTER hours. Shorter hours of darkness result in a reduction of the
body's natural melatonin production and that in turn results in increased production of
FSH and LH. FSH apparently causes some bone loss and may play a part also in the
development of adrenal growths. LH increased output been clearly demonstrated to cause
adrenal tumors. Studies can be easily found by using PubMed and other resources.
Abstracts from some of them are in the FHL Archives.
Whether a longer amount of dimness could harm ferrets, I don't know, but I can't imagine
any reason why it would.
Remember that ferret ancestry is NOT diurnal. Their ancestry is from individuals who lived
in burrows and mostly emerged only at times of low light. Burrows are incredibly dark.
Animals which normally have crepuscular activity (low light times around dusk and dawn)
can use some daytime or nighttime activity when times are hard (poor weather, poor
hunting, extra need, etc.) but naturally tend to return to staying in low light when active if
they have the chance.
Ferrets ever see better in very low light than diurnal species.
We humans tend to think in terms of what is natural and healthy for us and assume that
carries over to other species, but we are diurnal and our ancestors have been diurnal for
an extremely long time so the assumption that what is true for us is true for ferrets is
sorely misplaced and sometimes harmful.
See resources such as (as usual look at dates when you open them):
http://ferrethealth.org/archive/SG4455
http://ferrethealth.org/archive/SG7637
BEGIN QUOTE
That is a great question, and we are just
now getting the answers! Recent research by
Dr Nico Schoemaker at the Utrecht vet school
in Holland has helped answer your question.
Ferret adrenal glands have both LH and FSH
receptors on them just like the ovaries and the
testicles do. When ferrets are spayed or neutered
(as neonates by all of the major ferret farms) then the
adrenal glands start to respond to the high levels of LH
in the bloodstream. Keeping pet ferrets indoors under
"long day photoperiods" also adds to this problem. When
the adrenal glands are over stimulated, then they become
hyperplastic or neoplastic (cancer). So the short answer
is spaying and neuter pet ferrets at a young age is the major
cause of adrenal gland disease (just like it is in mice). Plus
keeping them in long day photoperiods adds to the problem.
That is why keeping a natural photoperiod or keeping them
in 14-16 hours of darkness per day is sometimes recommended.
There is also a possibility of a problem with the tumor suppressive
gene which is the 'genetic problem" that may add to the problem.
This problem has not been verified as of yet, but it is possible.
A viral cause is very unlikely.
Remember Lupron works by lowering the LH and FSH levels,
which stops the stimulation to the adrenals. Thus it may also be
useful to give Lupron to young ferrets to help prevent adrenal gland
disease!
Hope that helps,
Jerry Murray, DVM
END QUOTE
http://ferrethealth.org/archive/SG17116
http://ferrethealth.org/archive/FHL1843
BEGIN QUOTE
There has been some recent posts about how to
prevent adrenal gland disease, and there seems to
be some confusion on how some of the adrenal
medications work and how they might prevent adrenal
gland disease. I'll try to clear up some of that confusion.
Lupron and Deslorelin both work at the pituitary level to
stop the production of LH. Without LH there is no stimulation
to the adrenal glands. Without the stimulation from LH, the adrenal
gland stops producing hormones. Plus cases of hyperplasia (and
possibly even adenomas) may become smaller and may even return
to normal size with Lupron or Deslorelin treatment. However they
do not work directly on the adrenal glands. Melatonin works a little
differently. It works at the hypothalamus level to reduce LH production.
It may also work directly on the adrenal glands thru melatonin receptors
on the adrenal glands! This helps to prevent the adrenal gland from getting
bigger.
As far as using these products to prevent adrenal gland disease, starting
a juvenile ferret on them may prevent that ferret from getting adrenal
disease.
Likewise starting an adult ferret on them before they have signs of adrenal
gland disease may prevent them from getting adrenal disease as they
get older. However it requires Lupron monthly, year round, for the rest of
its life and not just one dose each spring.
As far as a genetic problem and adrenal gland disease, preliminary work
done by Dr Wagner at the U of Pitt has shown a defect in a tumor suppressor
gene (P53). This defect causes a loss of tumor suppression, so tumors
can form much easier and grow much bigger. He presented this info at
the symposium in Portland.
Hope that helps clear up some of the confusion.
Jerry Murray, DVM
END QUOTE
There is also work on MEN (Multiple Endocrinological Neoplasia) genetics from the UC
Davis team headed by Dr. Michelle Hawkins. I hope that I can get a copy of the final paper
on that when it is out.
Pub Med:
http://www.ncbi.nlm.nih.gov/sites/entrez
Use an assortment of search terms
ferret luteinizing
will bring you 54 articles
mustela luteinizing
will get you 77
adrenal luteinizing
will get you 2014
You can narrow things down with tighter searches or find related studies by going more
broadly. It's not a great search engine there but not terrible, either, esp. considering how
many papers there are, so some get missed and some accidently included in any search.
Once upon a time -- I guess last year perhaps. I went through study searches from
multiple places and found something a tad over 100 linking adrenal disease in ferrets to
increased in Luteinizing Hormone which in turn is a response to too much light and the
inability of neutered animals to send signals that would turn off the extra LH and FSH
production. Sadly, I no longer have that compilation.
So, the upshot is: AVOID TOO MUCH LIGHT for ferret; they are not humans!
I don't know whether having dim light punctuated by darkness could hurt, but it did not
harm that vet's ferrets and it did is the ancestral condition for ferrets.
Sukie (not a vet)
Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/fhc/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
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