Stressed out cat?

I recently acquired 2 kittens (3 months old now) - I got them at the end of August. I have 2 older cats - 10 yr old and an 8 yr old. My 8 yr old seems aggravated at the kittens since they pester him quite a bit. He visits the water dish more so than the food dish, but the water level doesn't really go down enough to say he's drinking excessively. I took him to the vet thinking something was wrong and they did blood work and a urinalysis. Everything checked out ok except for his triglycerides being quite a bit elevated after a 12 hour fast. He acts ok most of the time and plays some, but the eating thing has me bothered. I really have to coax him to eat. Has anyone gone through this before? Could this be a stress thing?