Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers find new form of hormone that helps songbirds reproduce

18.11.2003


Scientists have known for many years that auditory cues such as song can influence hormone release and the growth of gonads in songbirds, but how the brain picks out specific sounds, interprets them correctly and translates them into hormonal and behavioral signals has remained a mystery. New evidence suggests a third form of a key reproduction hormone could be a link between song and enhanced procreation in songbirds.



It’s a long-held tenet of avian biology that songbirds have just two types of a key reproduction hormone, gonadotropin-releasing hormone (GnRH), and only one actually triggers a seasonal "puberty" each spring in preparation for reproduction. But the new research shows a third form of the hormone, called lamprey GnRH-III-like hormone because it was first identified in lampreys, is also present in songbird brains.

The work by scientists from the University of Washington and the University of New Hampshire shows GnRH-III can trigger the release of luteinizing hormone from the pituitary gland and influence gonad growth, something only one of the other forms of GnRH does under normal conditions.


"This is interesting because many birds breed seasonally, and they time their breeding for favorable conditions in the spring," said George Bentley, a UW post-doctoral researcher in biology.

Bentley is lead author on a paper detailing the work that will be published in the December-January edition of the journal Brain, Behavior and Evolution. Co-authors are John Wingfield, a UW biology professor; Ignacio Moore, a UW post-doctoral researcher in biology; and Stacia Sower, a professor of biochemistry and molecular biology at the University of New Hampshire. The research also was presented earlier this month at the Society for Neuroscience annual meeting in New Orleans.

Like one other form of the hormone, GnRH-III is found in the hypothalamus, where it is released to the pituitary gland, which then triggers changes in the reproductive system, Bentley said. But unlike the other forms of the hormone, GnRH-III also is found in parts of the brain that initiate and process auditory cues.

"In some species, if a female bird hears a male of the species sing, her ovaries grow faster and she will lay more eggs," Bentley said.

In addition, tape-recorded songs from a male can trigger a rapid increase in testosterone of another male defending his territory, a phenomenon Wingfield has studied for many years.

In either case, the brain detects an external cue – birdsong – that triggers a physical or behavioral response, possibly both. Just how the responses are transmitted through the nervous system is unknown, Wingfield said. But finding a third form of GnRH in areas of the brain that produce and process birdsong holds the potential for ultimately identifying how cues such as song can be directly translated into hormone output that affects reproduction.

It could be the first step in showing that the hormone is released directly into the bloodstream from the song centers of the brain, rather than going through the hypothalamus, Wingfield said.

"We’ve never had a link like this for the GnRH-type molecule in these brain areas that produce and process birdsong," he said. "The fact that it’s there is unique to higher vertebrates."

The researchers note the importance environment can play in reproductive responses. For instance, previous studies have shown testosterone levels in the saliva of sports fans increases when their teams win, and it decreases when their teams lose. Likewise, the widely recognized home-field advantage in sports has recently been correlated to a higher salivary testosterone level in home-team players than in visitors.

But at a time when people are increasingly concerned about environmental changes, the researchers say, there is still very little information about how organisms respond to changes in various triggers – temperature change, for example – in their environments. The scientists plan further research with GnRH-III to try to determine how the brain interprets seemingly fleeting and subtle environmental cues such as temperature fluctuation, rivalry and vocalization. The response to these cues can have a profound impact on reproduction success, Bentley said.


For more information, contact Bentley at 206-543-7623 or gb7@u.washington.edu, or Wingfield at 206-543-7622 or jwingfie@u.washington.edu.

Vince Stricherz | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Life Sciences:

nachricht Rules of brain architecture revealed in large study of neuron shape & electrophysiology
18.06.2019 | Allen Institute

nachricht Schizophrenia: Adolescence is the game-changer
18.06.2019 | Université de Genève

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Schizophrenia: Adolescence is the game-changer

18.06.2019 | Life Sciences

Rules of brain architecture revealed in large study of neuron shape & electrophysiology

18.06.2019 | Life Sciences

Research highlights possible targets to help tackle Crohn's disease

18.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>