Navigation Links
Disabling mouse enzyme increases fertility

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
Washington University School of Medicine

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:
(Date:11/20/2015)... NXTD ) ("NXT-ID" or the ... mobile commerce market and creator of the Wocket® smart ... recently interviewed on The RedChip Money Report ... on Bloomberg Europe , Bloomberg Asia, Bloomberg Australia, ... NXTD ) ("NXT-ID" or the "Company"), a biometric authentication ...
(Date:11/18/2015)... 2015  As new scientific discoveries deepen our understanding ... healthcare providers face challenges in better using that knowledge ... addition, as more children continue to survive pediatric cancer, ... old age. John M. Maris, M.D ., ... Philadelphia (CHOP) . --> John M. ...
(Date:11/17/2015)... 17, 2015 Paris ... --> Paris , qui s,est ... DERMALOG, le leader de l,innovation biométrique, a inventé le ... et empreintes sur la même surface de balayage. Jusqu,ici, ... l,autre pour les empreintes digitales. Désormais, un seul scanner ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... ANGELES and HOLLISTON, Mass. ... Technology, Inc. (Nasdaq: HART ), a biotechnology company ... that CEO Jim McGorry will present at ... December 1, 2015 at 2:30 p.m. PT. The presentation ... below) for 30 days. Management will also be available ...
(Date:11/25/2015)... Nov. 25, 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: ... business and prospects remain fundamentally strong and highlights ... doxorubicin) recently received DSMB recommendation to continue the ... review of the final interim efficacy and safety ... Endpoint in men with heavily pretreated castration- and ...
(Date:11/25/2015)... -- Orexigen® Therapeutics, Inc. (Nasdaq: OREX ) today ... discussion at the Piper Jaffray 27th Annual Healthcare Conference ... is scheduled for Wednesday, December 2, at 8:00 a.m. ... will be available for 14 days after the event.  ... Corporate Communications and Business Development , BrewLife(858) 875-8629 ...
(Date:11/25/2015)... ... November 25, 2015 , ... Jessica Richman and Zachary Apte, ... their initial angel funding process. Now, they are paying it forward to other ... stage investments in the microbiome space. In this, they join other successful ...
Breaking Biology Technology: