A University of British Columbia zoologist has discovered a new corticosteroid hormone in the sea lamprey, an eel-like fish and one of the earliest vertebrates dating back 500 million years. These findings have shed light on the evolution of steroid hormones and may help conservation and management efforts for lampreys.
“This new discovery has significant scientific implications and application for lamprey conservation,” says principal investigator and lead author David Close, an assistant professor in the UBC Department of Zoology and director of the Aboriginal Fisheries Research Unit at UBC’s Fisheries Centre.
Close and colleagues at Michigan State University identified a corticosteroid hormone — called 11-deoxycortisol — in the sea lamprey that plays dual roles in balancing ions and regulating stresses, similar to aldosterone and cortisol in humans. The findings are published online this week in the Proceedings of National Academy of Sciences Early Edition.
Native to the Pacific Coast of North America and Asia, Pacific lampreys are an important ceremonial and subsistence food for Aboriginal peoples in the Columbia River basin. They are born in freshwater, swim out to the ocean as adults and return to freshwater to reproduce in similar habitats to Pacific salmon and trout. Adult lampreys can grow to approximately 75 cm long and use their sucker-like mouth to attach to other fish while in the ocean.
NB: Images of the Pacific lamprey and Prof. Close are available at http://www.publicaffairs.ubc.ca/2010/07/22/mr-10-105/.
“The origin of the corticosteroid signaling pathway has remained controversial over the past several decades because the identity of the ancestral corticosteroid has been elusive,” says Close.
“This discovery will help us better assess environmental and other stress factors on lamprey species — and provide insight into how stress-regulating hormones evolved from the earliest of vertebrates,” says Close, a member of the Cayuse Nation on the Confederated Tribes of the Umatilla Indian Reservation in the Pacific Northwest.
The study was initiated as part of efforts to restore populations of Pacific lamprey in the Columbia River Basin. Pacific lamprey numbers in the Columbia River have greatly declined since the construction of dams along the river.
Part of the study was conducted while Close was a researcher at the Department of Fisheries and Wildlife at Michigan State University. Major funding for this work was awarded to Close, while a fisheries scientist at the Confederated Tribes of the Umatilla Indian Reservation, from Bonneville Power Administration and additional support came from Michigan State University’s college of Agriculture and Natural resources, Great lakes fishery commission, and a fellowship from the National Institute of Mental Health.