When Hunger Goes Haywire

Bio prof wins NIH grant to study starving fish for clues to the biological basis of anorexia.

By Maureen O’Hagan | February 22, 2019

Why do some individuals refuse to eat even when they’re starving? This puzzling question lies at the heart of a three-year study by Prof. Suzy Renn [biology], who recently won a $421,374 grant from the National Institutes of Health to seek clues to the biological basis of anorexia and cachexia, a syndrome that afflicts many cancer patients.

Prof. Renn is a neuroscientist who studies the evolution of social behavior. She’s an expert on Astatotilapia burtoni, a species of cichlid fish that exhibits an unusual behavioral trait—the female holds her eggs in her mouth until they’re developed enough to be released. Sure, it’s a safe place for vulnerable eggs. But with a mouth full of eggs, these females go two weeks or more without eating. “They lose a ton of weight,” she says.

Gazing at the tanks of cichlids in her lab, she says that when it’s feeding time, the brooding females hang back while the other fish dine. Many other fish—and a lot of other animals, too—will eat their own young if they get hungry enough. Yet starving female cichlids “have a mouth full of yolky eggs and they don’t eat them,” she says. “It’s a kind of self-induced starving.”

The curious behavior of these fish led a former student to wonder: isn’t that kind of like anorexia? The question eventually led to this study. Renn and her students will focus on the areas of the fish brain that are involved in feeding behaviors. They will look at the brains of female cichlids engaged in voluntary starvation, and compare them to the brains of other cichlids, including non-brooding fish who have gone without food for a period. With the help of Prof. Anna Ritz, a computational biologist, she’ll look for patterns in the genes that are expressed in fish exhibiting different feeding behaviors

“Nature has evolved a mechanism that causes these cichlids to not eat when they’re starving,” Renn says. She hopes that the fish can shed light on the molecular mechanisms of anorexia and cachexia in people.

Tags: Awards & Achievements, Health/Wellness, Professors, Research