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:5/4/2016)... ... , ... A new collaboration will give more researchers access to the largest ... analytics leader SAS will provide researchers worldwide with data management and analytics tools to ... , The DCRI and SAS share the goal of greater transparency and openness ...
(Date:5/4/2016)... ... May 04, 2016 , ... Slepkow Slepkow & ... one of the top website design companies to create a state of the ... to the law firm's main practice areas. These practice areas include: real estate, ...
(Date:5/4/2016)... ... May 04, 2016 , ... Francesca Loparco, Co-Founder of Queen City Dream Cars, ... same-day LASIK procedure at Christenbury Eye Center. The entrepreneur struggled with her ... surgery the same day as her in-office consultation and eye exam. Francesca’s eyesight was ...
(Date:5/4/2016)... ... 2016 , ... Advanced Spine & Sport Medical Rehabilitation Center, which is renowned ... a free seminar on stem cell injections. The seminar is scheduled for Wednesday, May ... Telephone Road, Suite 110, Ventura, CA. There are only 10 seats available. , ...
(Date:5/4/2016)... Lenexa, KS (PRWEB) , ... May 04, 2016 ... ... Transtem™ Patient 2016, a powerful cellular therapy software application that helps ... life-saving treatments to patients. , Since Transtem’s initial launch, Mediware has continued to ...
Breaking Medicine News(10 mins):
(Date:5/4/2016)... , May 4, 2016 ... of the  "Global Multiple Myeloma Market and ... their offering.       (Logo: ... Market and Competitive Landscape Highlights 2016, provides ... Multiple Myeloma epidemiology, Multiple Myeloma market valuations ...
(Date:5/4/2016)... , May 4, 2016 ... of the  "Global Acute lymphocytic Leukemia Market ... to their offering.       (Logo: ... Acute Lymphocytic Leukemia Market and Competitive Landscape ... Lymphocytic Leukemia pipeline products, Acute Lymphocytic Leukemia ...
(Date:5/3/2016)... , May 3, 2016  Axiogenesis has acquired a major investment from Sino-German High-Tech Fund to further expand product ... Photo - http://photos.prnewswire.com/prnh/20160503/362921 ... ... ... ...
Breaking Medicine Technology: