IMMUNOREACTIVE GASTRIN IN DIFFERENTIAL AND DENSITY GRADIENT FRACTIONS OF RAT GASTRIC MUCOSA

Abstract

SUMMARY: Immunoreactive gastrin was measured in subcellular fractions of rat gastric mucosa. The sedimentational properties of subcellular gastrin-containing structures were distinct from those of mitochondria. After centrifugation in sucrose density gradients using a zonal rotor, the peak of immunoreactive gastrin was found in 1·17–1·18 g cm⁻³ density sucrose (1·35 m; 39·5%, w/w). A thermolabile component with ¹²⁵I-labelled gastrin-binding activity present in gastric mucosal homogenates and fractions was not associated with the gastrin storage vesicles sedimenting in density gradients.