Please Help Me. Scared Rising ALT and BUN

Question
Hello,
My 13 yr old red haired maine coon boy had a blood panel for the first time in 10/09.  His BUN was 43.  New vet said to recheck in a month BUN came down to 37.  He was just rechecked this week and the BUN was 43.  He is going to be checked again in May.  When the doctor mailed me the results of the kidney panel, I compared it against the two previous ones.  I noticed a rising ALT. I called her and she said it was within limits and not to worry.  She said if it is over the 100 limit, she would do an ultrasound.
In 10/09 the ALT was 49, in 11/09 it was 63, 3/09 it is 98.  I am terrified, as I recently lost one maine coon girl to gastro cancer.  My other one had a fibrosarcoma on his tail, and this boy has this.  The doctor said he needs to lose weight.  He is about 18 pounds.  She also said he should only be eating wet food.  No more Taste of the Wild as it has too much protein per vet. I had been giving them both Taste of the Wild hard in addition to the soft as of 11/09.  The reason we never did a blood panel before, was that the old vet who misdiagnosed my cats with the cancers, did not believe in blood work for healthy cats.  This woman vet is very kind and caring, but I am terrified even though she said not to worry it was within range. My concern is that it is rising.  I am terrified.  I ordered some SAMe from PetFood Direct, S-Adenosyl-100 (SAMe) by Vitality Systems for Small Dogs and Cats.  I did not run this by the vet, but a friend has her cat on it on the advice of her vet because of liver function. Another friend with many maine coons said she would not use the SAMe at this point. What should I do? If I use the SAMe will this hurt his kidney function. I cannot lose this beautiful boy.  I love him so much. I know this is very wordy, but I have no where to turn.  I cannot take any more loss of loved ones in my life. Can you please help me?

Thank You,
Maryann

Answer
The lab tests are OK for a cat that age. A BUN over 80 with an increasing Creatinine and Phosphorus is how we assess kidney function along with a urinalysis.  The ALT is not elevated and there are many other liver function tests that assess the liver, like bile acids and albumin. SAMe will not hurt anything.