You might consider checking an abdominal ultrasound to see if there is more going on with the liver than the blood work is showing.
You might ask the vet about trying a stomach soothing med such as Pepcid or Tagamet or Zantac.
You can read about dose amounts (and cautions) scrolling down on the pages here
http://www.petplace.com/drug-library/cimetidine-hcl-tagamet/page1.aspx
http://www.petplace.com/drug-library/famotidine-pepcid/page1.aspx
http://www.petplace.com/drug-library/ranitidine-hcl-zantac/page1.aspx
Something I've used to help an older dog past an undefined issue is NutriCal a sticky supplement from the pet supply store that you can put right in their mouths so they have to swallow it. Its nutritious on its own but can also perk up appetite. Similar products are VitaStat or the more liquid formula Dyne.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics