Comparison of fish and mammalian adipogenesis in vitro: Implications for regulating endocrine disruptors

Abstract

Adipogenesis, the process by which preadipocytes differentiate into mature fat cells, is closely associated with the development of obesity and metabolic syndrome. Identifying and classifying chemicals interfering with adipogenesis are needed for both human health and the environment. However, challenges remain in testing and interpreting data on chemical-induced adipogenesis. This study reviewed available in vitro fish adipogenesis assays, summarized the effects of chemicals on fish adipogenesis, and compared chemical-induced adipogenesis results between mammalian and fish assays. Primary fish adipocyte cultures have been developed for eight species of freshwater and seawater fish, with significant variation in culture media, particularly in adipogenic cocktails used. While lipid mixtures can enhance adipogenesis, they may not affect the commitment of multipotent progenitor cells to adipocyte linage and may not always be necessary for fish adipocyte cultures. Differences in chemical-induced adipogenesis between mammalian and fish assays may result not from species differences, but from variations in culture conditions, such as the composition of adipogenic cocktails and lipid mixtures, which can obscure the effects of chemicals on adipogenesis. There is a need for standardized adipogenesis assays, and developing OECD test guidelines is essential for their regulatory use. Fish adipogenesis assays can detect mechanisms of endocrine disruption that may not be apparent in mammalian cells, providing insights into mechanisms of action relevant to both human health and the environment. It is crucial to integrate adipogenesis data into the regulatory frameworks by expanding data requirements to include adipogenesis assays and developing reliability criteria for assessing adipogenesis studies.