Bombesin-like peptides in mammals

Area of Science:

• Gastroenterology
• Neuroscience
• Endocrinology

Background:

• Bombesin, a tetradecapeptide, is known for its effects on gastrointestinal and endocrine functions.
• Previous studies suggested the presence of bombesin-like peptides in mammalian tissues, but their exact localization and function remained unclear.

Purpose of the Study:

• To investigate the presence and characteristics of bombesin-like immunoreactivity in rat gut and brain.
• To determine the functional effects of these bombesin-like substances on gastrin secretion.

Main Methods:

• Radioimmunoassay was used to detect and quantify bombesin-like substances in acid extracts of rat tissues.
• Gel filtration and cation exchange chromatography were employed for the purification and fractionation of these substances.
• The effect of purified fractions on serum gastrin levels in rats was assessed following intravenous infusion.

Main Results:

• Bombesin-like immunoreactivity was detected in various parts of the rat gut, with highest concentrations in the stomach fundus.
• Significant amounts were also found in the small and large intestines, and in the hypothalamus of the brain.
• Fractionation revealed two major peaks of bombesin-like activity, with further resolution into two components.
• Infusion of these components increased serum gastrin levels in rats, comparable to synthetic bombesin.

Conclusions:

• Rat gut and brain contain bombesin-like substances with distinct chromatographic properties.
• These endogenous bombesin-like peptides can stimulate gastrin release, indicating a potential physiological role in regulating gastric secretion.
• The findings support the existence of a bombesin-like peptide system in mammals, analogous to that found in amphibians.