My rat is extremely sick

Question
Hello. My rat that i have owned for roughly two years is extremely sick. It has all happened over the last week or so. Here are the symptoms.
1. Weight loss, he feals real frail, his testicals seem to have shrivled quite a bit.
2. He is constantly eating but doesnt seem to be keeping on the weight.
3.He stumbles around doesnt really seem like he has complete control of his body.
4.Constantly sleeping. Normally he is active and running around.
5.No sneazing outside the occational.
6.He is a hairless rat and seems to be very ashy/flaky.

Any help would be appreciated thanks.

Answer
Sounds like heart or kidney related. Both can cause weight loss despite eating, although heart disease usually causes anorexia as well.

Is he drinking much? What about urinating?  Does his sides sink in when he breathes?
Is his body cooler than normal?

I suggest a vet visit right off. If its kidneys, not much can be done but support through diet and sometimes.
Check out the signs and symptoms of both heart and kidney disease below on my site:
http://www.sandyscrittercity.com/heartlungkidneydisease.htm

Do you have a vet that knows about rat care?

The ashy color may indicate dehydration. Try offering baby food and watermelon. Baby food, stage 1 is alot of water which may help replenish him, but he should be seen by the vet as stated and have a few tests run to find out what ails him.