Featured Research

from universities, journals, and other organizations

Obesity Gene Controls Bone Density Via Brain Pathway

Date:
January 24, 2000
Source:
NIH-National Institute Of Dental And Craniofacial Research
Summary:
The obesity gene, which helps maintain body weight and fertility, also plays a key role in controlling bone density, according to a report in the January 21 issue of Cell. Leptin, the hormone product of the obesity gene, acts as a natural bone inhibitor by telling the brain to slow down the rate of bone formation.

The obesity gene, which helps maintain body weight and fertility, also plays a key role in controlling bone density, according to a report in the January 21 issue of Cell. Leptin, the hormone product of the obesity gene, acts as a natural bone inhibitor by telling the brain to slow down the rate of bone formation. The Cell study is the first to show that the brain has a central role in controlling bone formation and density. Bone researchers are excited about this finding as it reveals a novel pathway that perhaps can be manipulated in ways to increase bone density and treat or even prevent osteoporosis.

An international team of investigators, led by Dr. Gerard Karsenty from the Baylor College of Medicine, with support from the National Institutes of Health, discovered the link between leptin, the brain, and bone density. "This is a very significant finding because it identifies an entirely new avenue for targeting osteoporosis therapies," said Dr. Karsenty. "Bone mass is essentially the product of a balancing act between cells that form new bone and other cells that digest old bone. Osteoporosis results from an imbalance in this equilibrium--specifically, an increase in bone resorption. Current therapies are aimed at slowing down resorption, but little is known about the formation side of maintaining bone mass. Identification of the leptin pathway, where the brain acts as the central component in building bone mass, opens a new realm of treatment approaches."

The link between leptin, the brain, and bone formation is another chapter in the story of this recently discovered hormone. It is known that leptin, which is produced by fat cells, acts on a region of the brain called the hypothalamus to help reduce body fat and maintain fertility. Karsenty and his colleagues unraveled the leptin-brain-bone connection by studying two groups of genetically obese mice.

One group of mutant animals was unable to make leptin; the other group could make leptin, but was unable to make the leptin receptor normally present in the hypothalamus. Both strains of mice were obese, but were also observed by X-ray analysis to have unusually dense bones. Further experiments confirmed that the leptin pathway had to be intact (both leptin and its brain receptor present) for bone formation to proceed at a normal rate. If the circuit is broken, by the absence of either leptin or its receptor, the brain directs bone-forming cells to become more active and make more bone.

The bones formed by leptin-deficient mice appear normal in terms of length and thickness, but the honeycombed interior is unusually dense, made up of thick, bony walls that surround areas of marrow. Not only are the bones dense, they are also as strong and flexible as normal bone. The situation is the reverse of what occurs in osteoporosis, where the honeycombed bone becomes thin and weak. While the absence of a functioning leptin circuit may be beneficial for building dense bone, the animals suffer the adverse effects of obesity and infertility. However, there is some encouraging evidence that leptin may use a separate pathway to control bone mass. Mice that produced half the normal amount of leptin were of normal weight, but also had dense bones. Yet another strain of mouse that was unable to produce either fat or leptin, nonetheless had very dense bones.

"It may be possible to manipulate the leptin pathway in a way that increases bone mass, but avoids the adverse effects on weight and fertility," said Dr. Karsenty.

Working with Dr. Karsenty were Drs. Patricia Ducy, Shu Takeda, and Jianhe Shen from the Baylor College of Medicine in Houston, Texas; Drs. Michael Amling, Matthias Priemel, Arndt Schilling, Frank Beil, and Johannes Rueger from the University of Hamburg, Germany; and Dr. Charles Vinson from the National Cancer Institute (NCI). The study was supported by the National Institute of Dental and Craniofacial Research (NIDCR) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). NCI, NIDCR, and NIAMS are components of the federal National Institutes of Health located in Bethesda, Maryland.


Story Source:

The above story is based on materials provided by NIH-National Institute Of Dental And Craniofacial Research. Note: Materials may be edited for content and length.


Cite This Page:

NIH-National Institute Of Dental And Craniofacial Research. "Obesity Gene Controls Bone Density Via Brain Pathway." ScienceDaily. ScienceDaily, 24 January 2000. <www.sciencedaily.com/releases/2000/01/000124074731.htm>.
NIH-National Institute Of Dental And Craniofacial Research. (2000, January 24). Obesity Gene Controls Bone Density Via Brain Pathway. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2000/01/000124074731.htm
NIH-National Institute Of Dental And Craniofacial Research. "Obesity Gene Controls Bone Density Via Brain Pathway." ScienceDaily. www.sciencedaily.com/releases/2000/01/000124074731.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins