Featured Research

from universities, journals, and other organizations

Key reproductive hormone in oldest living vertebrate identified

Date:
October 6, 2010
Source:
University of New Hampshire
Summary:
Researchers have identified the first reproductive hormone of the hagfish -- a gonadatropin -- representing a significant step toward unraveling the mystery of hagfish reproduction. At 500 million years old, hagfish are the oldest living vertebrate, predating the dinosaurs.

University of New Hampshire professor of biochemistry Stacia Sower and colleagues have identified the first reproductive hormone of the hagfish, the world's oldest living vertebrate.
Credit: Courtesy of Stacia Sower

Looking at a hagfish -- an eyeless, snot-covered, worm-like scavenger of the deep -the last thing that comes to mind is sex. Yet the reproductive functioning of these ancient vertebrates is such an enduring enigma that a gold medal was once offered to anyone who could elucidate it.

Related Articles


Although the prize expired, unclaimed, long ago, University of New Hampshire professor of biochemistry Stacia Sower and colleagues at two Japanese universities have identified the first reproductive hormone of the hagfish -- a gonadatropin -- representing a significant step toward unraveling the mystery of hagfish reproduction. Their findings, "Evolutionary origin of a functional gonadotropin in the pituitary of the most primitive vertebrate, hagfish," were published in the journal Proceedings of the National Academies of Science (PNAS) in September.

"This is a significant breakthrough with hagfish," says Sower, who was second senior author on this paper, co-authored by principal investigator Katsuhisa Uchida and Sower's long-time collaborator Masumi Nozaki, both of Niigata University in Japan. Gonadatropins (GTHs) are a protein secreted from the pituitary, stimulating the gonads (ovaries and testes) to produce and release the sex steroid hormones which prompt their growth and maturation. GTHs are produced in response to hypothalamic gonadotropin-releasing hormone (GnRH), what Sower calls the "master molecule" for reproduction in vertebrates; its discovery remains the holy grail of understanding hagfish reproduction.

At 500 million years old, hagfish are the oldest living vertebrate, predating the dinosaurs. "They're one of evolution's great success stories," says Sower, who has devoted the majority of her 30-year career researching hagfish and the similarly un-charismatic lamprey eels. "Here's this animal with a backbone that we don't know anything about." They're notoriously difficult to study, in part because their habitat is the ocean floor at 100 meters or more.

Yet their important evolutionary position makes hagfish worthy of scientific inquiry. "We look at the evolution of the hormones and receptors and say, 'have they retrained characteristics of their ancestral forms, or are they more similar to higher vertebrates?'" says Sower. "They're a key to understanding the evolution of later evolved vertebrates."

Compounding the urgency of better understanding hagfish reproduction is their growing importance as a fishery in the Gulf of Maine. Despite their vicious nature and least appealing characteristic -- the stress-induced secretion of mucous from up to 200 slime glands along their bodies -- hagfish are prized, particularly in Asian markets. Their tough, soft skin is marketed as "eel" skin for wallets, belts and other items ("Because they're not going to sell something that says 'hagfish,'" says Sower, pulling out her own flawless 20-year-old eel skin wallet).

Fished in the Gulf of Maine since 1992, hagfish have been fished out of the waters off Korea and Japan and overfished on the U.S. West coast. They also play a significant role in nutrient cycling and ocean-floor clean-up, feeding primarily on dead and dying fish. Lacking knowledge on their reproductive functions -- how, when and where they spawn -- the hagfish could be fished to extinction, says Sower.

Sower, who directs the Center for Molecular and Comparative Endocrinology at UNH, has worked with Nozaki on hagfish reproduction since both scientists were postdoctoral researchers at the University of Washington in 1980. The two, along with Hiroshi Kawauchi of Kitasato University in Japan, have shared students and researchers through a formal collaboration that's produced more than 30 papers. It's also, notes Sower, produced many failures as they've labored to identify the hagfish GTH.

"Now we're filling in the gaps of what we know," she says.

This work was supported in part by a grant from the National Science Foundation.


Story Source:

The above story is based on materials provided by University of New Hampshire. Note: Materials may be edited for content and length.


Journal Reference:

  1. K. Uchida, S. Moriyama, H. Chiba, T. Shimotani, K. Honda, M. Miki, A. Takahashi, S. A. Sower, M. Nozaki. Evolutionary origin of a functional gonadotropin in the pituitary of the most primitive vertebrate, hagfish. Proceedings of the National Academy of Sciences, 2010; 107 (36): 15832 DOI: 10.1073/pnas.1002208107

Cite This Page:

University of New Hampshire. "Key reproductive hormone in oldest living vertebrate identified." ScienceDaily. ScienceDaily, 6 October 2010. <www.sciencedaily.com/releases/2010/10/101005171038.htm>.
University of New Hampshire. (2010, October 6). Key reproductive hormone in oldest living vertebrate identified. ScienceDaily. Retrieved March 30, 2015 from www.sciencedaily.com/releases/2010/10/101005171038.htm
University of New Hampshire. "Key reproductive hormone in oldest living vertebrate identified." ScienceDaily. www.sciencedaily.com/releases/2010/10/101005171038.htm (accessed March 30, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, March 30, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Arthropod Fossil Might Be Relative Of Spiders, Scorpions

New Arthropod Fossil Might Be Relative Of Spiders, Scorpions

Newsy (Mar. 29, 2015) A 508-million-year-old arthropod that swam in the Cambrian seas is thought to share a common ancestor with spiders and scorpions. Video provided by Newsy
Powered by NewsLook.com
Vietnam Rice Boom Piles Pressure on Farmers and the Environment

Vietnam Rice Boom Piles Pressure on Farmers and the Environment

AFP (Mar. 29, 2015) Vietnam&apos;s drive to become the world&apos;s leading rice exporter is pushing farmers in the fertile Mekong Delta to the brink, say experts, with mounting costs to the environment. Duration: 02:35 Video provided by AFP
Powered by NewsLook.com
Raw: Lioness Has Rare Five-Cub Litter

Raw: Lioness Has Rare Five-Cub Litter

AP (Mar. 27, 2015) A lioness in Pakistan has given birth to five cubs, twice the usual size of a litter. Queen gave birth to two other cubs just nine months ago. (March 27) Video provided by AP
Powered by NewsLook.com
Jockey Motion Tracking Reveals Racing Prowess

Jockey Motion Tracking Reveals Racing Prowess

Reuters - Innovations Video Online (Mar. 26, 2015) Using motion tracking technology, researchers from the Royal Veterinary College (RVC) are trying to establish an optimum horse riding style to train junior jockeys, as well as enhance safety, health and well-being of both racehorses and jockeys. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins