Navigation Links
Findings raise new questions about evolution of hormones in mammals
Date:2/13/2009

SAN FRANCISCO, Feb. 13, 2009 New techniques used to examine hormones in feces and urine of mammals in the wild are yielding surprising results about hormones and evolution. The new techniques allow scientists to examine the social structure of a broader range of mammals.

San Francisco State Biology Professor Jan Randall will present findings at the AAAS meeting that examine social stress and how they correlate to survival and reproduction in mammals. The recent developments of noninvasive techniques such as tracking mammals to gather feces, and sensitive assays for fecal hormone metabolites, have allowed Randall to formulate a more complete picture of the relationships among behavior, social systems and hormone function in mammals in the wild. "Previously, much of the information we have on hormones came from limited sets of models like lab rats and mice," Randall said. "This non-invasive method is allowing us to ask evolutionary, physiological questions about animals in the wild in completely new ways."

While most of the recent field research has been conducted on rodents, researchers are beginning to conduct field work with whales, predatory animals and other mammals. Randall said it's important to challenge findings discovered in a lab setting. "We see species specific adaptation of control systems so we must rethink our evolutionary models of hormones," she said. "As we discover more in the field, we may discover many more unusual adaptations important for reproduction and survival."

When Randall began post-doc work in the late 1970s, research was confined to drawing hormones from blood or from trapping animals in the wild. Often, those methods yielded hormone samples that were tainted by heightened stress hormones when the animals were handled by researchers. If researchers can identify which specific animal produced the feces, it's possible to gain a better understanding of the effects of social stress and survival. "We need a specific sample and a social context to know what's going on hormonally," Randall said.

To study stress in natural populations, Randall collected feces from the great gerbil, Rhombomys opimus, in Uzbekistan over the course of six years, and the giant kangaroo rat, Dipodomys ingens, in California. The great gerbils are highly social rodents who live in high density communities. Some male gerbils would live with up to six females and their offspring. Randall wanted to know whether the social stress was affecting the male's ability to survive. For six years, Randall and her collaborators collected feces from specific males at various times throughout the year and found that males were stressed in large family groups but that outside factors like drought had a greater influence on survival than stress.

Randall and her graduate student, Julia Barfield, collected fecal samples during the breeding and non-breeding cycles of the giant kangaroo rat. They found significantly higher levels of testosterone in the summer non-breeding season than in the breeding season in both male and female kangaroo rats, which counters previous research conducted in a laboratory setting. Randall said the finding illustrates the flexibility of hormonal control systems and the importance of exploring them in wild populations.


'/>"/>

Contact: Michael Bruntz
mbruntz@sfsu.edu
415-338-1743
San Francisco State University
Source:Eurekalert

Related medicine news :

1. Center for the Study of Traumatic Encephalopathy announces new findings
2. New findings on old kidneys could enhance transplants, Stanford study shows
3. New findings shed light on why smokers struggle to quit
4. Bionovo to Present Recent Findings of BN108, its Anticancer Agent, at the 31st Annual San Antonio Breast Cancer Symposium
5. Breast cancer in men: Mammography and sonography findings
6. Initial Survey Findings on Diabetes Awareness Released by PatientAssistance.com
7. Best Practice Database Provides Key Findings for Biopharma Product Launch Evaluation
8. Tibotec presents interim findings for TMC435, an investigational genotype 1 hepatitis C treatment
9. NABP Findings Underscore Dangers of Purchasing Prescription Medicine Online and From Foreign Sources
10. New National Public Opinion Survey Reveals Important Findings on Oral Health Care Perceptions
11. New findings may improve treatment of inherited breast cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... ... June 27, 2016 , ... "FCPX editors can now reveal their media with ... X," said Christina Austin - CEO of Pixel Film Studios. , ProSlice Color ... users can now reveal the media of their split screens with growing colorful ...
(Date:6/27/2016)... ... June 27, 2016 , ... ... patient payment industry today announced its strategic partnership with Connance, a healthcare ... , The two companies’ proven, proprietary technology combine to provide health systems, ...
(Date:6/27/2016)... Park, KS (PRWEB) , ... June 27, 2016 , ... ... in retailers of Eyeglasses . , Millions of individuals in the United States ... eyeglasses have become a way to both correct vision and make a fashion statement. ...
(Date:6/26/2016)... Battle Creek, Michigan (PRWEB) , ... June 26, 2016 , ... ... abuse, joined as sponsor of the 2016 Cereal Festival and World’s Longest Breakfast Table ... held in honor of the city’s history as home to some of the world’s ...
(Date:6/26/2016)... ... ... PawPaws brand pet supplements owned by Whole Health Supply is ... of felines. The formula is all-natural and is made from Chinese herbs that have ... Kidney Support Supplement Soft Chews are Astragalus Root Extract and Rehmannia Root Extract ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... , June 24, 2016 ... appointment of Dr. Edward Futcher to ... Director, effective June 23, 2016.Dr. Futcher was also ... and Governance Committees.  As a non-executive member of ... expertise and strategic counsel to VolitionRx in connection ...
(Date:6/23/2016)... June 23, 2016 Research and ... Excipients Market by Type (Organic Chemical (Sugar, Petrochemical, Glycerin), ... Topical, Coating, Parenteral) - Global Forecast to 2021" ... The global pharmaceutical excipients market is projected ... CAGR of 6.1% in the forecast period 2016 to ...
(Date:6/23/2016)... 23, 2016 Research and Markets has ... 52" report to their offering. ... creates a favourable commercial environment for MedImmune to enter. The ... that will serve to drive considerable growth for effective anti-influenza ... to cap sales considerably, but development is still in its ...
Breaking Medicine Technology: