Introduction

A groundbreaking study has unveiled that bombesin, a neurohormone known for controlling appetite, is not just limited to humans and other vertebrates but also finds a surprising presence in invertebrates like starfish and other marine relatives. This revelation provides substantial insight into the evolutionary roots of hunger regulation across species.

What is Bombesin?

A small peptide, bombesin plays a crucial role in signaling the body to stop eating, effectively regulating hunger. The name "bombesin" originates from the fire-bellied toad (Bombina bombina), from which the peptide was first isolated in 1971. When bombesin is injected into mammals, it has been observed to decrease meal sizes and extend the time between meals, further reinforcing its role in the biological system that manages food intake.

Implications for Obesity Treatment

As the obesity epidemic continues to grow, researchers are investigating bombesin-like neurohormones found in the brain and gut. These molecules have the potential to be developed into weight-loss drugs, similar to popular medications like Ozempic, which are aimed at combating obesity.

The Research Study

Professor Maurice Elphick from Queen Mary University of London, along with his research team, delved into the evolutionary background of bombesin. They meticulously analyzed the genomes of various invertebrates and discovered genes that encode bombesin-like neurohormones within species such as the common starfish (Asterias rubens), sea urchins, and sea cucumbers.

"It felt like searching for a needle in a haystack," stated Professor Elphick, emphasizing the difficulty of finding these genes. Once the team identified the relevant sequences, they focused on understanding the function of the neurohormone in starfish, known as ArBN.

Molecular Structure and Findings

Utilizing advanced mass spectrometry, the researchers painstakingly determined the molecular structure of ArBN, enabling them to synthesize it for detailed testing. Their experiments revealed that ArBN significantly influences the unique feeding behavior of starfish, which involves everting their stomachs to digest prey such as mussels and oysters.

Dr. Weiling Huang, also from Queen Mary, observed that injecting ArBN into starfish led to contraction of their stomachs, suggesting that this hormone may play a role in stomach retraction once feeding halts. "When I injected ArBN into starfish with their stomachs everted, it triggered the stomach to retract back into the mouth," Dr. Huang reported. Remarkably, the starfish that received the ArBN injection took longer to begin feeding compared to those injected with water, indicating a delay in their feeding initiation.

Conclusion

This discovery not only deepens our understanding of appetite regulation in modern creatures but also hints at the existence of a shared biological framework that dates back approximately 500 million years, including our common ancestors with starfish and other vertebrates.

The full research findings will be published in the upcoming issue of the *Proceedings of the National Academy of Sciences*, further contributing to the scientific community's understanding of appetite control across diverse life forms. As further studies unfold, the implications for obesity treatment could become more significant, potentially reshaping approaches to managing dietary health in humans.