Featured Research

from universities, journals, and other organizations

Skeleton Is An Endocrine Organ, Crucial To Regulating Energy Metabolism

Date:
August 10, 2007
Source:
Columbia University Medical Center
Summary:
Researchers at Columbia University Medical Center have now identified a surprising and critically important novel function of the skeleton. They've shown for the first time that the skeleton is an endocrine organ that helps control our sugar metabolism and weight and, as such, is a major determinant of the development of type 2 diabetes.

A skeleton hand controlling the fate of a series of sugar cubes through a domino effect. Researchers present genetic evidence indicating that the skeleton is an endocrine organ regulating energy metabolism via 3 synergistic actions: regulation of pancreatic B-cell proliferation, insulin secretion and insulin sensitivity.
Credit: Karsenty Lab, Columbia University Medical Center, August 2007

Bones are typically thought of as calcified, inert structures, but researchers at Columbia University Medical Center have now identified a surprising and critically important novel function of the skeleton. They've shown for the first time that the skeleton is an endocrine organ that helps control our sugar metabolism and weight and, as such, is a major determinant of the development of type 2 diabetes.

The research, published in the August 10 issue of Cell, demonstrates that bone cells release a hormone called osteocalcin, which controls the regulation of blood sugar (glucose) and fat deposition through synergistic mechanisms previously not recognized. Usually, an increase in insulin secretion is accompanied by a decrease in insulin sensitivity. Osteocalcin, however, increases both the secretion and sensitivity of insulin, in addition to boosting the number of insulin-producing cells and reducing stores of fat.

In this published research, authors show that an increase in osteocalcin activity prevents the development of type 2 diabetes and obesity in mice. This discovery potentially opens the door for novel therapeutic avenues for the prevention and treatment of type 2 diabetes.

"The discovery that our bones are responsible for regulating blood sugar in ways that were not known before completely changes our understanding of the function of the skeleton and uncovers a crucial aspect of energy metabolism," said Gerard Karsenty, M.D., Ph.D., chair of the department of Genetics and Development at Columbia University Medical Center, Paul Marks Professor in the Basic Sciences, and senior author of the paper. "These results uncover an important aspect of endocrinology that was unappreciated until now."

Karsenty and his colleagues had previously shown that leptin, a hormone released by fat cells, acts upon and ultimately controls bone mass. They reasoned that bones must in turn communicate with fat, so they searched bone-forming cells for molecules that could potentially send signals back to fat cells.

The researchers found that osteocalcin, a protein made only by bone-forming cells (osteoblasts), was not a mere structural protein, but rather a hormone with totally unanticipated and crucial functions. Osteocalcin directs the pancreas' beta cells, which produce the body's supply of insulin, to produce more insulin. At the same time, osteocalcin directs fat cells to release a hormone called adiponectin, which improves insulin sensitivity.

This discovery showed for the first time that one hormone has a synergistic function in regulating insulin secretion and insulin sensitivity, and that this coordinating signal comes from the skeleton. Additionally, osteocalcin enhances the production of insulin-producing beta cells, which is considered one of the best, but currently unattainable, strategies to treat diabetes.

People with type 2 diabetes have been shown to have low osteocalcin levels, suggesting that altering the activity of this molecule could be an effective therapy. That hypothesis is supported by the Columbia research, which showed that mice with high levels of osteocalcin activity were prevented from gaining weight or becoming diabetic even when they ate a high fat diet. Analysis of mice lacking the osteocalcin protein showed that they had type 2 diabetes, increased fat mass, a decrease in insulin and adiponectin expression, and decreased beta-cell proliferation.

This research was supported by the National Institutes of Health, the American Diabetes Association, the Japan Society for the Promotion of Science, and the Pennsylvania Department of Health.

The researchers are now examining the role of osteocalcin in the regulation of blood sugar in humans and are continuing investigations into the relationship between osteocalcin and the appearance of type 2 diabetes and obesity.


Story Source:

The above story is based on materials provided by Columbia University Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

Columbia University Medical Center. "Skeleton Is An Endocrine Organ, Crucial To Regulating Energy Metabolism." ScienceDaily. ScienceDaily, 10 August 2007. <www.sciencedaily.com/releases/2007/08/070809130039.htm>.
Columbia University Medical Center. (2007, August 10). Skeleton Is An Endocrine Organ, Crucial To Regulating Energy Metabolism. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2007/08/070809130039.htm
Columbia University Medical Center. "Skeleton Is An Endocrine Organ, Crucial To Regulating Energy Metabolism." ScienceDaily. www.sciencedaily.com/releases/2007/08/070809130039.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
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