Textbook Problem

Effect of BPA on Insulin Secretion Bisphenol A (BPA) is an endocrine disruptor that may increase the risk of type 2 diabetes. Angel Nadal suspected that BPA disrupts insulin metabolism by activating an estrogen receptor on pancreatic islet cells. FIGURE 34.11 shows the results of one experiments. Cultured cells from human pancreatic islets were exposed either to BPA or to DPN, a chemical that binds to the estrogen receptor and activates it. Cells were then exposed to glucose, and their insulin Secretion was monitored.

FIGURE 34.11 Effects of BPA and DPN on glucose-stimulated insulin secretion. DPN is a chemical known to bind and activate estrogen receptors on pancreatic cells. A glucose concentration of 8 millimolar (mM) is equivalent to that of the blood after a meal.

Consider the two groups of cells exposed to glucose alone. How did the concentration of glucose affect their insulin secretion?

Summary Introduction

To determine: The way by which the glucose concentration affects the insulin secretion of cells.

Introduction: Diabetes mellitus is a condition in the body that leads to metabolic disorders with high blood sugar levels. There are two types of diabetes, type 1 and type 2. Type 2 diabetes is the most common form of diabetes that is seen among individuals. Here, the blood sugar level of the body always remains elevated because of the impaired response of the target cells toward the insulin hormone, which helps to maintain the blood sugar level.

There are many foreign substances that act like activators and inhibitor molecules, which disrupt normal hormonal activities. One such chemical is Bisphenol A (BPA) that acts like natural estrogen hormone and have an endocrine disrupting and diabetogenic activity.

Explanation of Solution

BPA is a synthetic compound present in epoxy resins and plastics, such as food containers, beverage bottles, and so on. Using different studies, the researchers have found that BPA directly acts on the pancreatic cells and increases the risk of type 2 diabetes mellitus. BPA activates the estrogen receptor that presents in the pancreatic cells and disrupts the insulin secretion Diarylpropionitrile (DPN), which is a chemical that has similar effects as BPA. It can also bind and activate the estrogen receptor as BPA and affect the insulin secretion.

Refer Figure 34.11 “Effects of BPA and DPN on glucose-stimulated insulin secretion” in the textbook. In the given experiment, researchers focused to determine the effects of BPA on insulin secretion. The human pancreatic cells were cultured and treated with BPA and DPN. Later, the cells were monitored for the insulin secretion. The cells that were exposed to glucose alone, without the treatment with BPA and DPN, secreted less insulin when compared to the treated ones. DPN treated pancreatic cells produced two times more than the insulin and those cells with BPA treatment secreted three times more than the insulin than that of the cells that were exposed to glucose alone.

Conclusion

BPA treated pancreatic cells produced three times more than the insulin, DPN treated cells secreted two times more than the insulin when compared to the cells that were only exposed to glucose.