CHICAGO, Dec. 21 (Xinhua) -- Treating ovariectomized mice with a combination of conjugated estrogens and the drug bazedoxifene triggers the expression of genes that improve metabolism and prevent weight gain, without stimulating the uterus and increasing risks of reproductive cancer, a study of the University of Illinois (UI) has found.

A group of researchers led by UI food science and human nutrition professor Zeynep Madak-Erdogan explored the effects of conjugated estrogens and bazedoxifene on the liver by analyzing gene transcription and the metabolism of about 150 chemicals in the blood.

The researchers fed 48 eight-week-old mice a high-fat diet in which 45 percent of the calories came from fat, and removed ovaries of 40 mice when they reached 10 weeks old to mimic the low-estrogen state of menopause. The mice then were randomly divided into five groups, each of which was treated for six weeks with a different combination of conjugated estrogens and bazedoxifene.

After the treatment period, the researchers euthanized the mice and weighed their adipose (fat) tissue, including their white adipose tissue, which stores energy in the form of lipids; and their mesenteric and perirenal adipose tissues, two forms of abdominal fat that are associated with the development of type 2 diabetes, insulin resistance, inflammation and other obesity-related diseases.

The researchers found that eight metabolites associated with the weight and health of the liver were down-regulated by the estrogen supplements, including several metabolites known to be misregulated in people with nonalcoholic fatty liver disease.

"Treatment with conjugated estrogens and bazedoxifene also prevented the weight gain that is often associated with postmenopausal decreases in estrogen and consuming a high-fat diet," said UI food science and human nutrition professor Zeynep Madak-Erdogan. "Animals in the treatment group had less fat mass and lower body weights than their peers in the control group. And their uteruses and mesenteric white adipose tissue weighed significantly less than those of their peers."

Recent studies suggest that hormone replacement therapy increases women's risks of reproductive cancers, and this has prompted physicians to exercise caution in prescribing hormones.

"Our study suggests that the combination of conjugated estrogens and bazedoxifene could improve metabolism without posing increased risk to the reproductive tissues," Madak-Erdogan said.

The findings have been published in online journal PLOS One.