Hi Sgreene, sorry I didn't see this sooner. My rat Matilda lived for a very long time with PT. She lived a full year very happily, and didn't even need to be fed mushy food until her last few weeks. She died oh so very peacefully, just fell asleep one day entirely out of the blue. You can see her last PT year here:
http://www.ratshackforum.com/forum/showthread.php?t=28219
A rat living so happily and for so long with PT is extremely rare. Our success was due to a combination of drugs that worked well(Prednisolone AND bromocriptine) in her case, luck, and an extremely early diagnosis. I'm not trying to make you any promises that might not keep through, but the best way to really raise your chances of the most happy time with your baby is definetly by treating the tumor with a comination of prednisolone+ bromocriptine or cabergoline.
This is how I understand the situation of a PT:
A PT is a tumor on the pituitary gland, at the base of the brain. While small, the tumor might not cause any symptoms, but then the second it puts pressure on the brain it does. That is why sometimes PT symptoms show up "overnight".
A lot of the symptoms of PT are due to swelling of the brain tissue around the tumor, putting pressure on the brain, and not the actual tumor itself. By giving a rat the drug prednisolone or prednisone, you retard the rat's immune system and inflammatory response to the tumor, reducing that swelling and therefore removing or lessening the symptoms.
It is important to remember that this is a temporary solution, because the drug does not affect the tumor itself. The tumor continues to grow, and after a while, depending on it's growth rate which varies, it in itself will cause pressure on the tissue and even the largest doses of prednisolone won't help.
Another thing to note is that prednisolone or prednisone reduces the entire immune system, to reduce that swelling. Because of that, the rat is often unable to fight off other infections. Many veterinarians prescribe a warning dose of baytril, an anti-inflammatory antibiotic, to be given to the rat to stop any infections before they set in.
So prednisolone/prednisone stops symptoms and increases comfort to the rat, but it does not stop or slow the growing of the tumor itself. To do that, the drug bromocriptine OR cabergoline is used. Cabergoline is more expensive and harder to find, but some users have better luck with it. Which you use is entirely up to you and how your rat reacts to it, but it is important to start treatment as early as possible. I suggest you give Bromocriptine a try, just because it is usually easier to find and cheaper(I got mine from the local CVS in pill form. I crushed the pills myself and mixed with some liquid. This "at home compounding" is much cheaper than having the drug compounded at a special pharmacy.).
Another drug some users use for PT is dex, if I'm not mistaken. It is usually only given in very dire situations when nothing else seems to be working, however. It is kind of the miracle drug, because it can be a kind of last-try-before-putting-to-sleep injection that allows some rats to jump back leaps and bounds for a small amount of time. From my understanding, dex does something similar to prednisolone/prednisone.
So that is PT as best as I can explain it, from what I understand. I can tell you already have a pretty good knowledge of this horrible thing that happens to our babies, but I hope maybe you gained something from my post. I also really, really hope that you give the prednisolone+bromocriptine combo a try, as it is the only way to ensure the longest/happiest life after finding out about PT. As you can tell from my thread, I went in entirely clueless but thanks to the awesome members of this website, and by pushing my vet to try these methods, my Matilda had almost record-breaking success with one of the most feared diagnosis our pets can get.
