A hormone that plays a role in regulating appetite may not work properly to promote feelings of fullness in people who are obese, according to a small new study.
On the flip side, glucagon -- which also plays a role in mediating blood sugar levels by signaling the release of glucose stores -- does work to suppress hunger in people with Type 1 diabetes, the study showed. Type 1 diabetes is a condition where not enough insulin, or none at all, is produced by the pancreas. Insulin is needed for glucose to enter cells, so if there's not enough insulin, high levels of glucose collect in the bloodstream.
The study, published in the Journal of Clinical Endocrinology & Metabolism, involved 11 obese people, 13 lean people and 13 people who had Type 1 diabetes. The participants were injected with either glucagon or a placebo.
Researchers kept track of the study participants' appetites in two ways: by measuring their levels of ghrelin (a hormone known to stimulate appetite; it's believed that glucagon is responsible for signaling the body to reduce levels of ghrelin as a means of regulating appetite), as well as measuring their self-reported feelings of appetite on a scale.
The lean participants experienced greater feelings of fullness after receiving the glucagon, as did the participants with Type 1 diabetes. However, there were no differences in feelings of fullness between the obese participants who received the glucagon, versus those who received the placebo.
"Once a person becomes obese, glucagon no longer induces feelings of fullness," study researcher Ayman M. Arafat, M.D., of Charité-University Medicine in Germany, said in a statement. "Further research is needed to determine why glucagon no longer suppresses appetite effectively in this population, even though they are otherwise healthy."