Motilin release in the pig

Area of Science:

• Gastroenterology
• Endocrinology
• Physiology

Background:

• Motilin is a gastrointestinal hormone found in the upper intestine of pigs and humans.
• In humans, motilin release is triggered by gastric acid.
• The release mechanism and physiological role of motilin in pigs are not well understood.

Purpose of the Study:

• To investigate the release of motilin in pigs in response to gastric acid stimulation.
• To determine the location and characteristics of motilin release in the pig's upper small intestine.
• To explore the potential physiological role of motilin in pigs.

Main Methods:

• Gastric acid was introduced into the upper small intestine of pigs to stimulate motilin release.
• Plasma motilin levels were measured before, during, and after stimulation.
• Immunohistochemistry was used to assess motilin levels in the intestinal tissue.
• Vascular occlusion of the stimulated segment was performed to assess the local nature of release.

Main Results:

• Gastric acid administration in pigs led to a significant increase in plasma motilin levels.
• This increase was associated with a marked reduction in immunostainable motilin in the upper small intestine.
• Occluding the blood supply to the stimulated intestinal segment immediately halted the rise in plasma motilin, confirming a local release.
• The apparent half-life of endogenous motilin was determined to be 3.9 minutes.
• No motilin release was observed after a meal in pigs.

Conclusions:

• Motilin release in pigs is a local phenomenon in the upper small intestine, triggered by gastric acid.
• The rapid clearance and lack of post-meal release suggest a specialized, yet currently speculative, physiological role for motilin in pigs.
• Further research is needed to elucidate the precise function of motilin in porcine gastrointestinal physiology.