Rat gastric histamine release: a sensitive gastrin bioassay

Area of Science:

• Physiology
• Pharmacology
• Biochemistry

Background:

• Gastrin's biological effects are assessed via rat stomach acid secretion and histamine release.
• Existing bioassays for gastrin have limitations in sensitivity and variability.

Purpose of the Study:

• To develop a more sensitive and reliable bioassay for gastrin (gastrin 1-17).
• To optimize experimental conditions for measuring gastrin's effects on isolated rat stomachs.

Main Methods:

• Utilized a totally isolated, vascularly perfused rat stomach preparation.
• Optimized calcium (Ca2+) concentration in the perfusate to enhance acid secretion sensitivity.
• Measured venous histamine release before and after gastrin administration to account for inter-stomach variability.

Main Results:

• Optimized Ca2+ concentration improved gastrin 1-17 (G-17) stimulation sensitivity for acid secretion from 65 to 16 pmol/l.
• Measuring histamine release improved sensitivity to 2 pmol/l G-17, surpassing previous bioassays.
• The developed assay demonstrates a detection limit comparable to radioimmunoassay.

Conclusions:

• The optimized perfused rat stomach model provides a highly sensitive gastrin bioassay.
• This method offers a reliable alternative for quantifying gastrin levels, comparable to established techniques like radioimmunoassay.