Diethylumbelliferyl phosphate is a selective, potent cholesterol esterase inhibitor. It blocks steroidogenesis primarily by preventing cholesterol transport into the mitochondria of steroidogenic cells. Inhibitors of cholesterol esterase are anticipated to limit the absorption of dietary cholesterol. IC50 = 11.6 microM. Substrate for testing OP-hydrolase activity (in particular the modified carboxylesterase E3 from Lucilia cuprina).