Featured Research

from universities, journals, and other organizations

'Clock' Genes Mediate Leptin Effects On Bone Formation

Date:
September 18, 2005
Source:
Baylor College Of Medicine
Summary:
The so-called "molecular clock" or clock genes play a crucial role in mediating the effect of the hormone leptin on the balance between the resorption and formation of bone, said Baylor College of Medicine researchers in a report in the current issue of the journal Cell.

HOUSTON (September 8, 2005) -- The so-called "molecular clock" or clock genes play a crucial role in mediating the effect of the hormone leptin on the balance between the resorption and formation of bone, said Baylor College of Medicine researchers in a report in the current issue of the journal Cell.

"We found that the clock genes are acting in bone cells to mediate the action of the brain on bone formation," said Dr. Gιrard Karsenty, professor in the department of molecular and human genetics at BCM. "There is a clock in bone, and the clock is there to control bone formation."

In a series of previous studies, Karsenty and his colleagues identified the hormone leptin as a critical regulator of bone mass. To achieve this function following its binding to hypothalamic receptors, leptin uses the sympathetic nervous system as a peripheral mediator to control bone formation. The mechanisms whereby sympathetic tone controlled bone formation in bone cells was still unknown.

In the present studies Karsenty and his colleagues demonstrated that genes of the molecular clock are expressed in bone cells, that their expression in these cells is regulated by leptin and the sympathetic tone, and that mice that have a disrupted molecular clock have a high bone mass but not other abnormalities usually associated with leptin deficiency such as obesity and sterility.

In previous studies, when Karsenty and his colleagues infused leptin into the brain, bone mass and bone formation decreased.

"To our surprise when we infuse leptin into the brains of mice with no clock genes, the mice had high bone mass, establishing that the clock genes are operating downstream (or after) of leptin presumably in bone cells," said Karsenty. Indeed, removing clock genes from bone cells results in an increase in bone formation. This work is the first in vivo demonstration that the molecular clock affects bone physiology.

"What is remarkable in terms of leptin biology is that the genes of the molecular clock are expressed in other cell types affected by leptin, yet the mutant mice we analyzed are, on a normal diet, lean and fertile, their only abnormality is to have to make too much bone," said Karsenty.

Leptin's role in appetite control has garnered much scientific and popular attention, but Karsenty's work demonstrates that the hormone's primary or at least ancestral role may have been to control bone mass, a function that was required during evolution before controlling appetite."

Others who participated in this research include Drs. Loning Fu and Millan S. Patel of BCM, Dr. Allan Bradley of the Wellcome Trust Institute Wellcome Genome Campus in Cambridge, England, and Dr. Erwin F. Wagner of the Research Institute of Molecular Pathology in Vienna, Austria. This work was supported by the U.S. National Institutes of Health and a Canadian Institutes for Health Research Fellowship.


Story Source:

The above story is based on materials provided by Baylor College Of Medicine. Note: Materials may be edited for content and length.


Cite This Page:

Baylor College Of Medicine. "'Clock' Genes Mediate Leptin Effects On Bone Formation." ScienceDaily. ScienceDaily, 18 September 2005. <www.sciencedaily.com/releases/2005/09/050916080343.htm>.
Baylor College Of Medicine. (2005, September 18). 'Clock' Genes Mediate Leptin Effects On Bone Formation. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2005/09/050916080343.htm
Baylor College Of Medicine. "'Clock' Genes Mediate Leptin Effects On Bone Formation." ScienceDaily. www.sciencedaily.com/releases/2005/09/050916080343.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Peace Corps Pulls Workers From W. Africa Over Ebola Fears

Newsy (July 30, 2014) — The Peace Corps is one of several U.S.-based organizations to pull workers out of West Africa because of the Ebola outbreak. Video provided by Newsy
Powered by NewsLook.com
Weather Kills 2K A Year, But Storms Aren't The Main Offender

Weather Kills 2K A Year, But Storms Aren't The Main Offender

Newsy (July 30, 2014) — Health officials say 2,000 deaths occur each year in the U.S. due to weather, but it's excessive heat and cold that claim the most lives. Video provided by Newsy
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