I've been trying to develop an assay for this. Its supposed to be pretty simple: Grow 3t3L1 cells and induce differentiation for a few days and they become functional adipocytes. Treat them with a catecholamine like isoproterenol, wait a bit and assay the cell medium for glycerol. Protocols have been published and companies selling adipolysis assay kits for years. My problem is I can't get it to work. Rather, I see a dual effect of isoproterenol on the glycerol assay. The first effect is that in the absence of another HRP substrate, isoproterenol behaves as an HRP substrate and generates color. The second effect is that it inhibits the color development from glycerol derived hydrogen peroxide. I can't figure out what I'm doing wrong. Anyone have experience with this?