Gastrin: levels and trophic action during advancing age.

Area of Science:

• Gastroenterology
• Endocrinology
• Aging Research

Background:

• Gastrin plays a key role in regulating gastric mucosal growth.
• Age-related changes in the endocrine system can affect gastrointestinal function.
• Understanding gastrin's role in aging is crucial for gastrointestinal health.

Purpose of the Study:

• To investigate changes in gastrin and somatostatin levels and cell densities in aging Fischer-344 rats.
• To assess the responsiveness of the gastric mucosa to the trophic action of gastrin in different age groups.
• To determine if age-associated proliferative activity in the gastric mucosa is linked to mucosal growth.

Main Methods:

• Measurement of serum and antral gastrin levels.
• Quantification of gastrin (G) and somatostatin (D) cell densities in the gastric antrum.
• Subcutaneous infusion of gastrin (G-17-I) or saline in rats aged 4, 8, and 16 months.
• Assay of gastric mucosal thymidine kinase activity, DNA, and protein content.

Main Results:

• Serum gastrin levels decreased, while antral gastrin levels increased with age.
• The density of G-cells decreased, leading to a higher D- to G-cell ratio in older rats.
• Gastrin infusion did not significantly increase mucosal DNA or protein content, despite increased thymidine kinase activity in saline-infused aged rats.

Conclusions:

• Aging in Fischer-344 rats is associated with altered gastrin and somatostatin cell dynamics.
• The gastric mucosa's responsiveness to gastrin's trophic action diminishes with age.
• Age-related increases in gastric mucosal proliferative activity occur independently of mucosal growth.