Increases of sugar intake caused by estradiol therapy can be reversed by blocking opioid receptors, according to a study in rats presented at the American Physiological Society’s annual meeting.

The major female sex hormone, estradiol, is used in several hormonal treatments including for birth control and menopausal symptoms.

For the study, the team of researchers gave estradiol to a group of rats which were infused with a blocker of opioid receptors (naltrexone) or with a saline (control group).  The results showed that naltrexone treatment reversed the increase of sugar intake caused by the estradiol.

Then in a following stage of the research, the reserachers injected DAMGO (synthetic compound that stimulated opioid system) in estradiol traded rats and in a control group. The results showed that DAMGO increased sugar intake in both groups, but the effect was smaller in the estradiol treated rats than in the control group.

These results suggest that while the opioid system plays a role in the increase of sugar intake as result of estradiol therapy, opioid receptors in the nucleus accumbens are not likely to be directly involved in this phenomenon.

Extra sugar intake caused by estradiol “is possibly mediated by the opioid system. However, a potential site of the action for this phenomenon remains unknown,” lead author Kurumi Iida said.


Source: Sience Daily