Lipase secretion from dispersed rabbit gastric glands.

We have measured gastric lipase activity in dispersed glands of rabbit stomach by quantitating the hydrolysis of tri[3H]olein. Lipase activity in isolated gastric glands was 200-400 nmol [3H]oleic acid released per milligram dry weight per minute. The percentage of lipase activity released during incubation for 30 min at 37 degrees C under basal conditions was 1.5-4.5%. Lipase release was stimulated by secretagogues: 10 nM cholecystokinin octapeptide (CCK-8) and 100 microM carbachol led to four- to sixfold and two- to threefold higher enzyme secretion, respectively, while histamine had no effect. Carbonyl cyanide m-chlorophenylhydrazone (30 microM) completely inhibited the CCK-8-induced lipase release, indicating that lipase secretion is dependent on mitochondrial oxidative energy; dibutyryl cGMP (1 mM) inhibited 1 nM CCK-8-stimulated but not 100 microM carbachol-stimulated secretion; atropine (1 microM) had the opposite effect. These studies suggest that secretion of lipase from isolated gastric glands is stimulated by at least two receptor mechanisms. These studies show that a lipase that hydrolyzes long-chain triglyceride is secreted by rabbit stomach mucosa and that the secretion of gastric lipase is stimulated by two different receptor mechanisms.