You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Unraveling the mode of action of an obesogen: Mechanistic analysis of the model obesogen tributyltin in the 3T3-L1 cell line. Obesogenic compounds are chemicals that have an influence on obesity development. This study was designed to unravel the molecular mechanisms of the model obesogen TBT, using microarray analysis in the 3T3-L1 in vitro system, and to evaluate the use of toxicogenomics for obesogen screening. The microarray results revealed enrichment of Gene Ontology terms involved in energy and fat metabolism after 10days of TBT exposure. Pathway analysis unveiled PPAR signalling pathway as the sole pathway significantly enriched after 1day and the most significantly enriched pathway after 10days of exposure. To our knowledge, this is the first study delivering an in depth mechanistic outline of the mode of action of TBT as an obesogen, combining effects on both cell physiological and gene expression level. Furthermore, our results show that combining transcriptomics with 3T3-L1 cells is a promising tool for screening of potential obesogenic compounds.
{"Chemical": ["TBT", "tributyltin"]}