Abstract
1. The effect of octapeptide of cholecystokinin-pancreozymin (CCK(8)), bethanechol, cholera toxin, glucagon and vasoactive intestinal polypeptide (VIP) on amylase secretion and lactic dehydrogenase (LDH) release from isolated rat pancreatic acini was studied.2. In isolated rat pancreatic acini, in the absence of theophylline in the medium, amylase secretion was increased by 65-78% with 10(-7) and 10(-6) M-cholera toxin. In the presence of theophylline, amylase secretion was increased by 43-56% with 10(-7) and 10(-6) M-cholera toxin following a 90 min incubation. No effect was observed in the presence of theophylline at 30 and 60 min. The effect of cholera toxin was potentiated by CCK(8) at 60 and 90 min.3. In the absence of theophylline in the medium, amylase secretion was increased by 81-118% with 10(-5) and 10(-4) M-glucagon and 86% with 10(-6) M-VIP at 60 min. In the presence of theophylline in the medium, amylase secretion was increased by 53-246% with 10(-9) to 10(-6) M-glucagon and 111-158% with 10(-7) and 10(-6) M-VIP respectively. The effect of glucagon and VIP was potentiated by CCK(8).4. Potentiation of the rate of amylase release due to glucagon (10(-5) M) and VIP (10(-6) M) occurred during the first 15 min of incubation.5. Release of LDH was not increased by any of these agents.6. It is concluded that cyclic AMP rise (due to cholera toxin, glucagon and VIP effect) increased amylase secretion from rat pancreatic acinar cells. This effect is less marked than in the guinea-pig pancreas and is potentiated by agents mobilizing cellular Ca(2+) (CCK(8) and bethanechol).7. These data indicate species-specific variation in the action of cyclic AMP in the pancreas.