SECRETION OF INTRINSIC-FACTOR FROM CULTURED RAT GASTRIC CHIEF CELLS

Intrinsic factor (IF) is a vitamin B-12 binding protein that is secret ed from the gastric mucosa. We tested secretagogues which stimulate IF secretion in rat gastric perfusion and found that carbachol and chole cystokinin octapeptide (CCK-8) stimulated secretion, but histamine and tetragastrin did not. To confirm these results, we examined LF secret ion from isolated rat chief cells. For this purpose, we established an enzyme immunoassay (EIA) using an avidin-biotin peroxidase complex to measure small amounts of IF. To prepare an anti-rat IF, IF was isolat ed from the stomach, and was injected into a rabbit for immunization. Rat gastric chief cells were isolated from the gastric mucosa with Dis pase and a Percoll gradient centrifugation, and were cultured. We exam ined the effects of chemicals by adding them to culture dishes of chie f cells in a CO2 incubator. Released IF in culture medium was determin ed by EIA. Carbachol, CCK-8 and secretin stimulated IF secretion from cultured chief cells, while histamine and tetragastrin did not; Forsko lin and A23187 also stimulated the secretion. We concluded that carbac hol and CCK-8 stimulated IF secretion via an increase of intracellular Ca2+ concentration and that secretin did so via a cAMP accumulation.