At a recent meeting of the Endocrine Society in Philadelphia new findings by British researchers were presented regarding hormone interactions with weight problems.
Dr. Simon Aylwin, a consultant from the King’s College Hospital in London, England, presented data showing that peptide hormone PYY levels were much lower in patients who were significantly obese versus normal weight controls.
As Dr. Stephen Bloom’s research group from Imperial College, London, UK had shown earlier, with a meal rich in calories the gut produces the PYY hormone in a way that with higher amounts of calories in food consumed more of the hormone PYY is secreted into the blood stream. The new information that was discussed at the meeting of the Endocrine Society was the fact that these hormone signals are registered in the hypothalamic tissue, a part of the brain situated just above the pituitary gland. It has been known for a long time that weight is regulated by a satiety centre in the hypothalamus. Now it has been appreciated that there are at least two or more pathways of registering weight related hormone signals: one being the gut related PYY hormone that tells the brain that enough food was consumed in a meal, and secondly leptin hormone signals where the hormone leptin is secreted from the fatty tissues in the body, which tells the satiety centre of the brain that not as much food needs to be consumed when our weight has reached a certain threshold.
Dr. Aylwin measured PYY hormone levels in a number of different groups of patients such as in patients who were obese, in patients who had gastric bypass surgery done and in a group who only had gastric banding done. They observed that the group who had bypass surgery done had a higher than normal response of PYY hormone release as a response to a meal. This enabled them to adhere to low calorie meals without any hunger pangs and this group of patients did well in terms of weight control on the longterm.
In contrast to this the group with gastric banding had a flat response curve to the stimulus of a meal with respect to the PYY hormone as did patients with obesity. The low PYY levels in response to meals likely explains why these patients continue to eat too much making their weight loss efforts more difficult.
Dr. Aylwin explained that with future research efforts new forms of medications could be developped that mimic the effects of the PYY hormone leading to satiety and allowing patients to control their weight easier. Dr. Linda Fish, an endocrinologist from the University of Minnesota, mentioned that for excessive obesity with a body mass index of more than 45 the only effective therapy right now would be the invasive gastric bypass procedure. With an anologue type medication that would have the same effect as the PYY hormone, many patients might be able to have persistent weight loss with these new medications allowing them to lose weight persistently without bypass surgery. However, results of this type of research likely would take about 10 years before a new drug would be available to the public.
This summary is based on an article in the July 15, 2003 issue of the Medical Post (page 50) as well as on the newsdesk article entitled “Obesity-is it all in the mind?” in The Lancet Neurology Volume 2, Number 1, January 2003.
Link to related topic (nasal spray for obesity).
Last edited December 9, 2012