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Lesson Seven: Obesogens

Module Two: The Evidence for Obesogens

Overview

Video Lecture

Ligand

View the online lecture for the details necessary to understand this module's key ideas.

Learning Objectives

At the end of this module, students will be able to:

  • Outline some of the major hormones and receptors that play a part in adipogenesis and lipid balance, factors that can affect weight gain
  • Explain how the processes of adipogenesis and lipid balance can be affected by Endocrine Disrupting Chemicals (EDCs)

Earlier in this course, you learned about Endocrine Disrupting Chemicals (EDCs), and how they prevent hormones from doing the jobs they were meant to do—either by mimicking them, or by preventing them from properly binding to their receptors. In this module we will explore how EDCs can act through nuclear receptor (NR) pathways that affect fat cell production (adipogenesis) and lipid homeostasis too, potentially causing obesity. EDCs that do this are called obesogens.

Our appetites and metabolism are controlled by multiple hormones—they tell us when we’re hungry, and when we’re full—when we should be burning calories, and when we should be stashing that extra energy away as fat. They tell us when we should increase our fat cell production or maintain lipid balance. If something disrupts this equilibrium, problems will usually follow.

All of these processes are regulated by the specific nuclear receptors (NRs) RXR and PPAR gamma which regulate fat cell development and control cell differentiation (essentially telling stem cells what they’re going to be when they grow up). Both of these turn genes on and off by interacting with hormone ligands. NRs are very sensitive—they respond to low levels of hormone.  The problem is that lots of chemicals can bind to these receptors, and even at low levels can deeply affect the balance of lipids in our bodies.

To explore this module's material in depth, view the lecture.

Key Points

  • Lipid production and balance is moderated by hormones.
  • These hormones work by binding to nuclear receptors (NRs).
  • Endocrine Disrupting Chemicals (EDCs) interfere with hormones by acting through NR pathways, and these can potentially disrupt adipogenesis and lipid balance, which can make us fatter.