Featured Research

from universities, journals, and other organizations

Tiny RNA molecule may have role in polycystic ovary syndrome, insulin resistance

Date:
March 19, 2013
Source:
Medical College of Georgia at Georgia Regents University
Summary:
A group of tiny RNA molecules with a big role in regulating gene expression also appear to have a role in causing insulin resistance in woman with polycystic ovary syndrome and, perhaps, in all women, researchers report.

A group of tiny RNA molecules with a big role in regulating gene expression also appear to have a role in causing insulin resistance in woman with polycystic ovary syndrome and, perhaps, in all women, researchers report.

Research in the journal Diabetes, indicates that high activity levels of a microRNA called miR-93 in fat cells impedes insulin's use of glucose, contributing to PCOS as well as insulin resistance, said Dr. Ricardo Azziz, reproductive endocrinologist and PCOS expert at the Medical College of Georgia at Georgia Regents University.

"This is one of the first reports of a defect that may occur both in women who are insulin resistant and, in particular, in women with PCOS," said Azziz, the study's corresponding author. "Identifying this molecular mechanism helps us understand these common conditions better and points us toward targeted therapies to correct these problems in women."

PCOS affects about 10 percent of women and is characterized by excess male hormone, irregular ovulation and menstruation and is associated with an increased risk for insulin resistance, which can lead to diabetes and heart disease.

Researchers looked at fat cells from the lower abdomen of 21 women with PCOS and 20 controls. In all the women with PCOS, they found over expression of miR-93 and decreased expression of GLUT4, a key protein that regulates fat's use of glucose for energy. Fat, a large organ in even a thin individual, is where a lot of glucose usage via insulin occurs.

GLUT4 expression was lowest in the women with PCOS who also were insulin resistant. They also found the expression was low in members of the control group who were insulin resistant.

"Low levels of GLUT4 in fat appear to be affecting insulin resistance in general and to have a more dramatic impact in PCOS," Azziz said. MiR-93 was known to impact GLUT4 in other cell types and to have a role in reproduction, infertility and lipid metabolism. "There has been no clear mechanism to describe insulin resistance in PCOS and we believe this is one of the pathways," said Dr. Yen-Hao Chen, cell biologist at MCG and the study's first author.

Interestingly, the investigators found that two other microRNAS -- miR-133 and miR-223, which are known to regulate GLUT4 expression in heart muscle cells -- also were over expressed but only in the fat cells of PCOS patients, Chen said. This exclusivity implicates the tiny molecules in the underlying condition of PCOS, Chen said. The researchers don't know yet if the two are related to miR-93. "We are just beginning to understand the role of these small molecules in PCOS and insulin resistance and much work remains to be done," Azziz said.

Follow up studies include better understanding just how microRNAs impact GLUT4, identifying other microRNAS that do -- including looking further at miR-133 and 223 -- and identifying what factors impact the tiny RNA molecules.

Humans use both insulin and non-insulin related mechanisms to use blood sugar, or glucose, as an energy source.

Azziz and his colleagues recently showed in Journal of Clinical Endocrinology & Metabolism that women with PCOS have defects in both mechanisms. In fact, PCOS women who had the most difficulty controlling glucose via insulin were also the ones with the greatest declines in their ability to use non-insulin approaches. More typically, when insulin resistance increases, the body's non-insulin dependent usage increases, apparently to help compensate.


Story Source:

The above story is based on materials provided by Medical College of Georgia at Georgia Regents University. Note: Materials may be edited for content and length.


Cite This Page:

Medical College of Georgia at Georgia Regents University. "Tiny RNA molecule may have role in polycystic ovary syndrome, insulin resistance." ScienceDaily. ScienceDaily, 19 March 2013. <www.sciencedaily.com/releases/2013/03/130319091725.htm>.
Medical College of Georgia at Georgia Regents University. (2013, March 19). Tiny RNA molecule may have role in polycystic ovary syndrome, insulin resistance. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2013/03/130319091725.htm
Medical College of Georgia at Georgia Regents University. "Tiny RNA molecule may have role in polycystic ovary syndrome, insulin resistance." ScienceDaily. www.sciencedaily.com/releases/2013/03/130319091725.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

$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
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
West Africa Gripped by Deadly Ebola Outbreak

West Africa Gripped by Deadly Ebola Outbreak

AFP (July 28, 2014) The worst-ever outbreak of the deadly Ebola epidemic grips west Africa, killing hundreds. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. 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