no direct impacts, though its positive impacts on GH efficacy (through plasma insulin reduction) should have some effect on net protein synthesis and probably lowered muscle catabolism as well.
Interesting about the lowered muscle catabolism. I ran out of r-ala last week, and I dropped weight since then, and it wasn't fat. I lost a good 5lbs and I was eating the same minus the r-ala. Don't know if that was the only thing behind it, but it's an awful big coincidence.