The authors conclude that epigenetic changes resulting from poor maternal diet and aging lead to reduced expression of Hnf4a in pancreatic beta cells, reducing insulin production and increasing the risk of diabetes. The findings provide an understanding of how a mother's diet influences the expression of Hnf4a in adult offspring and, consequently, their metabolic health. There are also more general implications as the study proposes an epigenetic mechanism by which foetal programming might influence long term health.
New role for thyroid hormones act in the brain to regulate energy balance
Thyroid hormones are important regulators of energy balance that enable the body to convert the food we eat into energy. Thyroid hormones also regulate body temperature by stimulating specific type of fat cells, called brown fat, to burn energy and boost heat production.
People with hyperthyroidism lose weight because they burn more energy than they consume. Until now it was assumed that much of the increase in energy expenditure (and the subsequent weight loss) was caused by the direct action of thyroid hormones on brown fat.
This new research, published in Nature Medicine, shows that the brain also has an important role in this effect. Specifically that the effects of thyroid hormones on brown fat are mediated via the hypothalamus, a specialized region of the brain that also controls food intake.
"These results open up a potentially important new area of obesity research in which the hypothalamus could be targeted to activate brown fat and promote weight loss. They might also provide a new approach to developing treatment for other diseases such as severe forms of hyperthyroidism or cancer-induced weight loss", comments Professor Toni Vidal-Puig, senior author of the study.