In a new study, scientists discovered that G-1, a cancer-fighting compound, can reduce fat in obese mice.
Scientists are studying GPER, the G protein-coupled estrogen receptor that G-1 activates, because GPER affects specific breast cancer cells. When breast cancer drugs like tamoxifen and fulvestrant block estrogen receptors in a cell’s nucleus, they also activate GPER, which is found in cell membranes.
Estrogen is considered a female hormone. Low levels of estrogen in women is a hallmark of menopause, and postmenopausal women also have higher rates of heart disease, high blood pressure, obesity, and diabetes.
To get a better comprehension of how G-1 might affect metabolism in postmenopausal women, scientists studied mice with low estrogen levels.
During the study, low-estrogen female mice gained weight rapidly and quickly became obese and diabetic. When treated with a compound called G-1, the mice lost weight. The compound also cures their diabetes.
Eric Prossnitz, Ph.D., Distinguished Professor and Chief Division of Molecular Medicine Department of Internal Medicine The University of New Mexico School of Medicine, said, “Their metabolism changed. The mice showed increased energy expenditure.”
Male produce estrogen at low levels. Considering it, scientists also studied male mice. During the study, male mice were fed a high-fat diet, which made them obese and diabetic.
When treated with compound G-1, the mice did not lose weight; they did not gain additional weight either, like the untreated mice. More importantly, their diabetes improved.
In an experiment with low-estrogen female mice, scientists found that they lost weight, and their diabetes improved when they were treated with G-1.
Prossnitz said, “This result suggests that G-1 has separate effects on obesity and diabetes. The G-1-treated male mice were metabolically healthier, even though they were still obese.”
“These results could point to a sex difference in the effects of the drug or in the way GPER signals in the cells of males and females.”
Scientists next studied brown fat cells to clear their concept of how G-1 increases energy expenditure. Brown fat cells generate heat instead of storing excess calories as fat. The results were surprising: when treated with G-1, the cells expended more energy.
Prossnitz said, “This fits nicely with what we saw in mice and suggests that G-1 may reduce obesity by targeting brown fat cells that burn extra calories.”
Scientists are further planning to examine how signals from GPER induce the cellular changes that cause more energy to be used.
They will soon start the long path toward clinical trials that will test the ability G-1 to fight obesity and diabetes in people.
Through this discovery, scientists hope to help 93 million obese Americans fight their fat.
The study is published in Science Translational Medicine.