3.beta-3-[2-(Diethylamino)ethoxy]androst-5-en-17-one hydrochloride or U18666A, an amphipathic cationic amine, is a cell permeable research tool drug that inhibits cholesterol synthesis and trafficking, and also a weak inhibitor of hedgehog (Hh) signaling. U18666A had been used in several models both in vivo and in vitro to mimic Niemann-Pick type C disease (NPC) and for assessing the importance of molecular trafficking through the lysosomal pathway in other conditions such as atherosclerosis, Alzheimer's disease, and prion infections. U18666A also provided animal models for such disorders as petite mal (absence) epilepsy and cataracts. U18666A inhibits the enzyme desmosterol reductase responsible for reducing the desmosterol in cholesterol biosynthesis, and also blocks LDL-(low density lipoprotein) cholesterol transport from the lysosomes into the endoplasmic reticulum thereby increasing the level of caveolina-1 located within the plasma membrane caveolae. U18666A was shown to be a potent antagonist of alpha4beta2 neuronal nicotinic acetylcholine receptors and may be useful as a tool in the functional characterization and pharmacological profiling of nAChRs.