Differentiation between the calcium‐dependent effects of cholecystokinin‐pancreaozymin and the bicarbonate‐dependent effects of secretin in exocrine secretion of the rat pancreas.

Abstract

SUMMARY1. Differentiation between the secretary effects of pure natural cholecystokinin-pancreozymin (COK-PZ) and those of synthetic secretin was studied in the isolated pancreas of the rat perfused with a standard solution containing both Ca2+ and HCO3-, a Oa2+-deficient solution, or a HC-G-deficient solution.2. Secretin induced a dose-dependent increase in the flow of pancreatic juice and a slight but definite increase in amylase output which was also dependent upon the dose of secretin.3. The increase in the flow of pancreatic juice, induced by continuous stimulation with secretin (5 Ivy dog m-u./ml.), was completely abolished during perfusion with a HCO3--deficient solution, but was only slightly suppressed during perfusion with a Ca2+-deficient solution.4. The increase in flow, induced by continuous stimulation with CCK-PZ (5 Ivy dog m-u./ml.), was partly affected by the deprivation of HCO3-, but was strongly inhibited by the deprivation of Ca2+. The CCK-PZ-induced amylase output was not affected by the deprivation of HOG-, but was significantly inhibited by the deprivation of Ca2+.5. The present results favour the view that CCK-PZ acts on the acinar cells to increase both amylase output and juice flow, whereas secretin acts on centro-acinar and terminal duct cells to increase mainly juice flow.

A Comparison of Secretory Actions of VIP, Secretin and CCK-PZ in the Isolated and Perfused Kitten Pancreas

“…The present experiments have also demonstrated that CCK-PZ hyperpolarizes the pancreatic acinar cell. These results accurately coincided with those obtained in the isolated and perfused rat pancreas (Kanno, 1972(Kanno, , 1975Kanno andSaito 1976, 1978 ;Kanno et al, 1977).…”

“…In rat pancreas, it was shown that secretin induced a dose-dependent increase in the flow of pancreatic juice and a slight but definite increase in amylase output which was also dependent upon the dose of secretin (Kanno and Yamamoto, 1977) . In the kitten pancreas, the present experiments have shown that secretin induced a dosedependent increase in the flow but a negligible increase in the pancreatic protein output except for a transient increase which may quite well be due to flushing of the pancreatic protein retained in the ductal lumen.…”

Potentiation of cholecystokinin-induced exocrine secretion by both exogenous and endogenous insulin in isolated and perfused rat pancreata.

“…In recenit years it has become apparent that CCK also stimulates release of a Cl--rich fluid, which is presumiieed to originate from acinar cells and is distinct from the juice secretedl by the pancreatic ducts (24,25). Because both exogenous and endogenous insulin potentiate pancreatic fluidl as well as enzyme secretion, it is likely that insulin acts on a process common to both.…”

The Influence of Calcium on the Control of Fluid Secretion in the Cockroach Salivary Gland

“…cockroach salivary gland , blowfly salivary gland (Prince & Berridge, 1973), rat parotid gland (Petersen & Pedersen, 1974;Rudich & Butcher, 1976;Petersen, Ueda, Hall & Gray, 1977) and exocrine pancreas (Agent, Case & Scratcherd, 1973;Petersen & Ueda, 1976;Kanno & Yamamoto, 1977;Petersen, 1977 a andLaugier &Petersen, 1980). These have led to the proposal of intracellular calcium-dependent stores of some substance (possibly calcium itself) essential for the response to stimulation.…”