A Closer Look at Obesogens: Lipid Homeostasis Disruption in Daphnia

In this study, the researchers found evidence that TBT activated signaling pathways related to molting and reproduction, presumably by increasing transcription of the retinoid X receptor (RXR) gene.3 In vertebrates, the nuclear receptor known as peroxisome proliferator-activated receptor γ partners with the RXR to stimulate fat cell differentiation and lipid storage.10 These receptors are known targets for TBT.11 However, LeBlanc says it would be premature to call this a model organism for the study of obesogens. “The molecular pathways that are affected [by TBT] in vertebrates don’t exist in Daphnia,” he says. Bruce Blumberg, a professor of developmental and cell biology at the University of California, Irvine, agrees it may be premature to call Daphnia a model for the study of obesogens. Obesogens are defined as chemicals that produce weight gain by increasing the number and/or size of adipocytes or by modulating lipid metabolism.12 Although lipid transfer is clearly important for fecundity of the animals, Blumberg points out that “the perturbation of lipid transfer from mother to egg in itself isn’t necessarily an obesogenic effect.” Blumberg was not involved in the current study. Yet if chemicals that cause mammals to get fatter can also perturb lipid dynamics in an ecological context, there could be implications beyond obesity, says Michele La Merrill, a toxicologist at the University of California, Davis. “Although this study is not evaluating invertebrat...
Source: EHP Research - Category: Environmental Health Authors: Tags: Featured News Science Selection Animal Models August 2015 Ecology and Wildlife Endocrine Health Metabolism Reproductive Health Source Type: research