New Discovery: Three Bombesin-like Peptides May Help Control Reproductive Smooth Muscle Movement

A research group led by Dr. Keisuke Obara, Dr. Kento Yoshioka, and Professor Yoshio Tanaka from the Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, has discovered that certain naturally occurring peptides in the body can trigger contractions in the vas deferens—a muscular tube that carries sperm in the male reproductive system. These peptides, known as bombesin-like peptides (neuromedin B, gastrin-releasing peptide, and neuromedin C), were found to play an active role in smooth muscle movement in this organ. The team also found that the mRNA for a specific receptor, the bombesin BB₂. receptor—which responds to these peptides—is highly expressed in the tissue. This suggests that the peptides likely act through this receptor to induce contractions. This discovery provides new insights into the regulation of the reproductive system and may contribute to the development of novel treatments for urogenital disorders. The findings were published in the scientific journal Biological and Pharmaceutical Bulletin in March 2025.