Pepsinogens: physiology, pharmacology pathophysiology and exercise

Area of Science:

• Biochemistry
• Gastroenterology
• Exercise Physiology

Background:

• Human gastric mucosa secretes pepsinogens (PGA and PGC), precursors to pepsin, vital for digestion.
• Pepsinogen synthesis and secretion are regulated by complex feedback mechanisms involving cAMP and Ca(2+).
• Serum pepsinogen levels serve as non-invasive markers for gastric mucosa status and gastrointestinal diseases.

Purpose of the Study:

• To investigate the relationship between gastrointestinal distress, hormonal changes, and pepsinogen levels in athletes undertaking high-altitude marathon running.
• To evaluate if extreme exercise and hypobaric-hypoxic environments induce gastric mucosa necrosis.

Main Methods:

• Serum levels of Pepsinogen A (PGA) and Pepsinogen C (PGC), gastrin, and cortisol were measured in athletes after a marathon at 4300m.
• Gastrointestinal symptoms and hormonal alterations were compared between athletes and a control group.
• Electrophoretic separation and molecular weight determination of pepsinogens were described.

Main Results:

• Gastrointestinal symptoms occurred in 40% of athletes; however, no gastric mucosa necrosis was observed.
• Athletes showed significant increases in gastrin and cortisol post-race, with a decreased PGA/PGC ratio.
• Control subjects exhibited no gastrointestinal or hormonal alterations, except for a circadian decrease in cortisol.

Conclusions:

• High-altitude marathon running does not induce gastric mucosa necrosis, despite physiological stress.
• Observed hormonal alterations (gastrin, cortisol) are likely related to central nervous system activation due to exercise and altitude stress.
• The decreased PGA/PGC ratio in athletes may reflect physiological responses to extreme conditions rather than gastric pathology.