Navigation Links
Protein that regulates hormones critical to women's health found in pituitary
Date:1/11/2009

MADISON University of Wisconsin-Madison researchers have solved the mystery surrounding a "rogue protein" that plays a role in the release of neurotransmitters and hormones in the brain.

The scientists found abundant amounts of the puzzling protein whose main location and function were unknown until now in a specific area of the pituitary gland. Like someone at a control knob, the protein may adjust the release of the two hormones that come almost exclusively from the posterior pituitary: oxytocin, which controls many reproductive functions, and vasopressin, which controls fluid balance.

"The findings raise very interesting possibilities for women's health, in which rising and falling hormone levels play a key role in many biological processes," says senior author Meyer Jackson, a professor of physiology at the UW-Madison School of Medicine and Public Health (SMPH). More studies will be needed to better understand the protein, he adds.

The study appears in the Jan. 11 Nature Neuroscience.

The research focused on Syt IV, a maverick member of the synaptotagmin family of 17 proteins, which are present in both mice and humans. Synaptotagmins are usually embedded in the membranes of small sacs, or vesicles, filled with neurotransmitters and hormones within nerve terminals. When an electrical impulse from one cell reaches a nerve terminal, it triggers the release of calcium, which in turn triggers the spilling out of the vesicle's contents neurotransmitters and hormones so they can act on other cells.

"Most synaptotagmins are triggering molecules that drive a vesicle's membrane into the membrane that surrounds a neighboring cell so that chemicals inside the vesicle can come out," says Jackson.

But Syt IV is an odd member of the family because it doesn't bind to calcium, said Jackson. In addition, Syt IV is found only sparsely in most parts of the brain. But Jackson and his colleagues were surprised a few years ago when they discovered large amounts of it in the posterior pituitary, one of the three primary parts of the gland.

He teamed with Edwin Chapman, a Howard Hughes Medical Institute investigator, fellow SMPH physiology professor and synaptotagmin expert. The UW-Madison researchers conducted high-powered biophysical measurements to understand exactly what Syt IV does in the pituitary. They made a thorough comparison of the pituitaries from normal mice and mice in which Syt IV had been knocked out.

The work showed conclusively that, like other members of the synaptotagmin family, Syt IV resides on vesicles. But unlike the others, Syt IV doesn't trigger neurotransmitter or hormone release.

"It does not simply translate a calcium signal into a command for hormone release," says Jackson. "Unlike other synaptotagmins, Syt IV tunes the triggering command and determines whether the same electrical impulse will let a large or small amount of hormone out of the nerve terminal."

This ability to modulate hormone release may have important implications for pregnancy, birth, lactation and the menstrual cycle, all of which are linked to fluctuations in oxytocin levels.

"Any change in the body that entails releasing more or less of this hormone into the bloodstream could well be a result of the brain's making more or less of this protein," says Jackson, who for two decades has studied the powerful pea-sized pituitary located at the base of the brain.

For example, early release of oxytocin can lead to premature birth, a phenomenon that has intrigued Jackson for a long time.

"It's quite possible that Syt IV levels change during pregnancy, birth and even post partum," he conjectures.

Confirming the possibility will be the next order of business for the Wisconsin researchers and others.

Jackson's interest in the effects of oxytocin, also known as the "love hormone," is not restricted to the female reproductive system. Last year, his team showed that Viagra acts in the posterior pituitary by enabling electrical impulses to release more oxytocin.


'/>"/>

Contact: Dian Land
dj.land@hosp.wisc.edu
608-261-1034
University of Wisconsin-Madison
Source:Eurekalert

Related biology news :

1. Dartmouth researchers find new protein function
2. Studies offer guide as protein interaction mapping comes of age
3. A protein that protects against Alzheimers?
4. Methods for studying DNA repair and protein modification are featured in CSH Protocols
5. Johns Hopkins scientists pull proteins tail to curtail cancer
6. Apolipoprotein(a): A natural regulator of inflammation
7. Motor nerve targeting to limb muscles is controlled by ephrin proteins
8. New technique is quantum leap forward in understanding proteins
9. Krumlauf Lab demonstrates modulation of gene expression by protein coding regions
10. Just a little squeeze lets proteins assess DNA
11. Stowers Institutes Workman Lab discovers novel histone demethylase protein complex
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/29/2017)...  higi, the health IT company that operates the ... , today announced a Series B investment from ... The new investment and acquisition accelerates higi,s strategy to ... population health activities through the collection and workflow integration ... collects and secures data today on behalf of over ...
(Date:3/24/2017)... Controller General of Immigration from Maldives Mr. Mohamed Anwar and ... international IAIR Award for the most innovative high security ePassport and eGates  ... ... Maldives Immigration Controller General, Mr. Mohamed Anwar ... right) have received the IAIR award for the "Most innovative high security ...
(Date:3/23/2017)... 2017 Research and Markets has announced the ... Trends - Industry Forecast to 2025" report to their offering. ... The Global ... of around 8.8% over the next decade to reach approximately $14.21 ... market estimates and forecasts for all the given segments on global ...
Breaking Biology News(10 mins):
(Date:10/9/2017)... ... October 09, 2017 , ... The award-winning American Farmer ... first quarter 2018. American Farmer airs Tuesdays at 8:30aET on RFD-TV. , With ... with the challenge of how to continue to feed a growing nation. At the ...
(Date:10/9/2017)... Antonio, Texas (PRWEB) , ... ... ... new study published on October 5, 2017, in the medical journal, Epilepsia, ... equivalence with the gold standard, video EEG, in detecting generalized tonic-clonic seizures ...
(Date:10/7/2017)... Mass. , Oct. 6, 2017  The ... work of three scientists, Jacques Dubochet, Joachim ... breakthrough developments in cryo-electron microscopy (cryo-EM) ... technology within the structural biology community. The winners ... Scientists can now routinely produce highly resolved, three-dimensional ...
(Date:10/5/2017)... ... , ... LabRoots , the leading provider of educational and interactive virtual ... to cancer research with a month-long promotion supporting the advancement of breast cancer research ... use promo code PinkRibbon to get 10 percent off their purchase of every the ...
Breaking Biology Technology: