Navigation Links
Disabling mouse enzyme increases fertility
Date:5/16/2008

St. Louis, May 16, 2008 Changing the sugars attached to a hormone produced in the pituitary gland increased fertility levels in mice nearly 50 percent, a research group at Washington University School of Medicine in St. Louis has found. The change appears to alter a reproductive "thermostat," unveiling part of an intricate regulatory system that may one day be used to enhance human fertility.

"To adjust for the right amount of key reproductive hormones such as estrogen and testosterone, we may someday alter the sugars that are added to this hormone or others like it," says the group's leader, Jacques Baenziger, M.D., Ph.D., professor of pathology and immunology and of cell biology and physiology.

The report appeared recently in The Journal of Clinical Investigation.

Sugars are the most common addition to hormones and other proteins after they have been assembled from instructions in DNA. Nearly all proteins in the blood and on the surface of cells have sugars attached. Scientists believe sugar attachments modify and adapt proteins, enabling them to fill more than one job or changing the way they do their jobs in different contexts. But direct demonstration of such changes has been challenging.

Baenziger found a unique set of sugars consistently added to luteinizing hormone, which is part of a feedback loop between the pituitary, the reproductive organs and the liver. The loop cycles up and down over time, producing periodic peaks in other reproductive hormones and triggering regular events such as the ovaries' release of eggs.

For their study, Baenziger's laboratory genetically disabled one of the enzymes that attaches sugars to luteinizing hormone in mice. This enzyme isn't the only one to add sugars to the hormone, so the alteration changes the mix of sugars rather than eliminating them completely.

Initially, we didnt seem to see much of a difference in the animals, Baenziger says. But then someone came to me and said, We have too many animals. Were constantly weaning mice!

A closer look showed that the mice were having nearly 50 percent more pups than normal, and that the liver removed the altered hormone from the blood more slowly. In addition, female mice were maturing earlier, were always receptive to male overtures for mating and had a disrupted ovulatory cycle. Males had higher levels of testosterone and females had higher levels of estrogen. Surprisingly, the altered female mice were also better mothers: They ate their pups less often.

"One could speculate that fertility problems in some humans may be partly related to a defect somewhere in this very complicated regulatory system," says Baenziger. "They may have the wrong proportion of some of these sugars, or the receptors that clear the sugar-hormone combination from the blood might not bind as well."

Baenziger, who recently won a five-year, $3.3 million grant renewal from the National Cancer Institute, wants to learn more about the segments in the reproductive hormones that single them out for the addition of unique sugars. He hopes to use that information to search for other proteins that receive similar treatment.

"We know these systems for adding sugars are well-regulated, but we're just starting to get a sense for how they are controlled and how far-reaching their effects can be," he says. "I think we're going to see much more of this kind of alteration and regulation of protein properties via added sugars in many other important areas of biology."


'/>"/>

Contact: Michael Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
Source:Eurekalert

Related biology news :

1. Study reveals 2 genes linked to disabling arthritis
2. Mouse can do without mans most treasured genes
3. Mouse study: When it comes to living longer, its better to go hungry than go running
4. Negligent, attentive mouse mothers show biological differences
5. Scientists successfully treat new mouse model of inflammatory bowel disease
6. Book is the first high-resolution digital mouse brain atlas designed for Web applications
7. Dissecting the genetic components of adaptation of E. coli to the mouse gut
8. CSHL scientists identify and repress breast cancer stem cells in mouse tissue
9. New chimeric mouse model for human liver diseases, drug testing
10. Looking through the eyes of a mouse, scientists monitor circulating cells in its bloodstream
11. Cancer-resistant mouse discovered
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/21/2016)... Columbia , June 21, 2016 ... to the new role of principal product architect ... named the director of customer development. Both will ... chief technical officer. The moves reflect NuData,s strategic ... in response to high customer demand and customer ...
(Date:6/16/2016)... 2016 The global ... reach USD 1.83 billion by 2024, according to ... Technological proliferation and increasing demand in commercial buildings, ... drive the market growth.      (Logo: ... development of advanced multimodal techniques for biometric authentication ...
(Date:6/9/2016)... leader in attendance control systems is proud to announce the introduction of fingerprint attendance ... the right employees are actually signing in, and to even control the opening of ... ... ... Photo - ...
Breaking Biology News(10 mins):
(Date:12/8/2016)... ... December 08, 2016 , ... ... control cells — optogenetics — is key to exciting advances in the study ... spatially patterned light projected via free-space optics stimulates small, transparent organisms and excites ...
(Date:12/8/2016)... , Dec. 8, 2016  Anaconda BioMed S.L., a ... of the next generation neuro-thrombectomy system for the treatment ... Tudor G. Jovin, MD to join its Scientific Advisory ... a strategic network of scientific and clinical experts to ... of the ANCD BRAIN ® to its clinical ...
(Date:12/8/2016)... Iowa (PRWEB) , ... December 08, 2016 , ... This ... asynchronous approvals for biotech crops. The authors focus on the economic effects in countries ... global approval of new biotech crops and the resultant risk of low level presence ...
(Date:12/8/2016)... Savannah River Remediation LLC group evaluated ... NT-MAX Lake & Pond Sludge and Muck ... conjunction with Hexa Armor/ Rhombo cover manufactured by ... Discharge Elimination System requirements. The Savannah ... of elevated pH levels, above 8.5, especially during ...
Breaking Biology Technology: