Boosting levels of gut hormones may battle obesity

Melbourne: Increasing the levels of two gut hormones simultaneously may be a new weapon in the fight against obesity, scientists claim.

In the constant cross talk between our brain and our gut, two gut hormones are already known to tell the brain when we have had enough to eat.

Researchers from Sydney`s Garvan Institute of Medical Research suggest that boosting levels of these hormones simultaneously may be an effective new weapon in the fight against obesity.

Dr Shu Lin, Dr Yan-Chuan Shi and Professor Herbert Herzog, have shown that when mice are injected with PYY3-36 and PP, they eat less, gain less fat, and tend not to develop insulin-resistance, a precursor to diabetes.

At the same time, the researchers have shown that the hormones stimulate different nerve pathways, ultimately, however, affecting complementary brain regions.

Drug companies are in the process of conducting pre-clinical trials to examine the separate effects of boosting the hormones PYY3-36 and PP.

Until now, there is no research to indicate the detailed molecular interactions that might occur when they are boosted in tandem.

When used together, the hormones independently, yet with combined force, reduce the amount of neuropeptide Y (NPY) produced by the brain, a powerful neurotransmitter that affects a variety of things including appetite, mood, heart rate, temperature and energy levels.

Each hormone also communicates with a different part of the arcuate nucleus in the hypothalamus, a region of the brain where signals can cross the normally impermeable blood/brain barrier.

The stimulated regions then produce other neuronal signals deep within the hypothalamus, bringing about a powerful combined effect.

"There are many factors that influence appetite control - and we now realise that there won`t be a single molecular target, or a single drug, that will be effective," said Shi.

"It will be important for drug companies to try different combinations of targets, to see which combinations are most potent, and at the same time have no side effects, or at least minimal side effects," Shi said.

The study was published in the journal Obesity.