I've done bis and tris before a few times (with prop incidentally)...
There was some speculation in the 90s that local injections with test prop stimulated IGF1 production in the site muscle.....not sure how true that actually is though...but we just put prop in arms and delta just in case it was lol
There was the study done on chickens with npp that showed site injection growth. My ass should be huge by now from gear