Hormone-driven effects on eating, stress mediated by same brain region

September 25, 2007

MADISON - A hormone system linked to reducing food consumption appears to do so by increasing stress-related behaviors, according to a new study.

Mediated by a hormone receptor protein known as the corticotropin-releasing factor type 2 (CRF2) receptor, the system has attracted recent interest for its role in regulating food intake, say Vaishali Bakshi and Ned Kalin, professors in the Department of Psychiatry at the University of Wisconsin-Madison School of Medicine and Public Health.

"With the increasing focus on obesity, people are interested in finding targets that can be used to develop drugs that will reduce appetite and food intake without a lot of side effects," Bakshi says.

Previous studies have shown that activation of this receptor decreases the amount of food voluntarily eaten by hungry rats, an effect called induced anorexia. This finding led some researchers to suggest that the CRF2 receptor system might be a promising target for therapies to combat obesity.

However, the new study, appearing Sept. 26 in the Journal of Neuroscience, shows that CRF2 receptors in a single brain region, the lateral septum, mediate both feeding and behaviors associated with stress, suggesting this protein may not be an ideal therapeutic target.

By selectively stimulating the CRF2 receptors in the lateral septum, Bakshi and her colleagues found that the treated rats ate less overall - roughly half as much as untreated rats - because they spent less time at it.

"The reason that the rats were eating less after having CRF2 receptors stimulated in the lateral septum was because instead of eating they were spending most of their time exhibiting stress-like behaviors," such as excessive grooming, which Bakshi says has been proposed to represent a type of coping behavior.

In addition, the eating suppression may be secondary to the apparent stress-inducing effects of the receptor. "We found anxiety-like responses at smaller doses than those required to get the reduction in feeding," Bakshi says. "In terms of the chicken and the egg, it suggests that maybe the stress comes first and that the reduction in feeding comes second."

The role of CRF2 receptors in stress responses does not come as a complete surprise, Bakshi says, because the related protein CRF1 receptor exerts similar influences in a different brain region and has been studied for its involvement in anxiety disorders and clinical depression.

However, the finding does suggest that the CRF2 receptor pathway is not likely to be a good choice for the hoped-for obesity treatment.

"This is a cautionary tale," says Bakshi. "We're refuting a global statement that CRF2 stimulation reduces ingestive behavior without eliciting stress-like effects."
The work was carried out in the lab of Ned Kalin and other authors on the study include Sarah Newman, Stephanie Smith-Roe, and Kimberly Jochman. The work was supported by grants from the UW HealthEmotions Research Institute, Meriter Hospital, and the National Institutes of Health.

University of Wisconsin-Madison

Related Obesity Articles from Brightsurf:

11 years of data add to the evidence for using testosterone therapy to treat obesity, including as an alternative to obesity surgery
New research covering 11 years of data presented at this year's European and International Congress on Obesity (ECOICO 2020) show that, in obese men suffering from hypogonadism (low testosterone), treatment with testosterone injections lowers their weight and improves a wide range of other metabolic parameters.

Overlap between immunology of COVID-19 and obesity could explain the increased risk of death in people living with obesity, and also older patients
Data presented in a special COVID-19 session at the European and International Congress on Obesity (ECOICO 2020) suggests that there are overlaps between the immunological disturbances found in both COVID-19 disease and patients with obesity, which could explain the increased disease severity and mortality risk faced by obese patients, and also elderly patients, who are infected by the SARS-CoV-2 virus that causes COVID-19 disease.

New obesity guideline: Address root causes as foundation of obesity management
besity management should focus on outcomes that patients consider to be important, not weight loss alone, and include a holistic approach that addresses the root causes of obesity, according to a new clinical practice guideline published in CMAJ (Canadian Medical Association Journal) http://www.cmaj.ca/lookup/doi/10.1503/cmaj.191707.

Changing the debate around obesity
The UK's National Health Service (NHS) needs to do more to address the ingrained stigma and discrimination faced by people with obesity, says a leading health psychologist.

Study links longer exposure to obesity and earlier development of obesity to increased risk of type 2 diabetes
Cumulative exposure to obesity could be at least as important as actually being obese in terms of risk of developing type 2 diabetes (T2D), concludes new research published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]).

How much do obesity and addictions overlap?
A large analysis of personality studies has found that people with obesity behave somewhat like people with addictions to alcohol or drugs.

Should obesity be recognized as a disease?
With obesity now affecting almost a third (29%) of the population in England, and expected to rise to 35% by 2030, should we now recognize it as a disease?

Is obesity associated with risk of pediatric MS?
A single-center study of 453 children in Germany with multiple sclerosis (MS) investigated the association of obesity with pediatric MS risk and with the response of first-line therapy in children with MS.

Women with obesity prior to conception are more likely to have children with obesity
A systematic review and meta-analysis identified significantly increased odds of child obesity when mothers have obesity before conception, according to a study published June 11, 2019 in the open-access journal PLOS Medicine by Nicola Heslehurst of Newcastle University in the UK, and colleagues.

Obesity medicine association announces major updates to its adult obesity algorithm
The Obesity Medicine Association (OMA) announced the immediate availability of the 2019 OMA Adult Obesity Algorithm, with new information for clinicians including the relationship between Obesity and Cardiovascular Disease, Diabetes Mellitus, Dyslipidemia, and Cancer; information on investigational Anti-Obesity Pharmacotherapy; treatments for Lipodystrophy; and Pharmacokinetics and Obesity.

Read More: Obesity News and Obesity Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.