DURHAM, N.H. -- 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.
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 a
|Contact: Beth Potier|
University of New Hampshire