[Responses of exocrine pancreas to a six month oral treatment by methadone in rats (author's transl)].

Pancreatic secretion and pancreatic enzyme contents were studied in rats given orally methadone for six months (10 to 50 mg . kg-1 . day-1 in drinking water). The main results were as follows: 1. In conditions of acute pancreatic fistula under urethane anesthesia: (a) basal concentration of total protein increased in the juice (+23 p. 100, p less than 0,05). The increase in trypsinogen appeared larger than that of other enzymes; (b) under conditions of maximal stimulation by 2 deoxy-glucose (2 DG), all secretory parameters were increased (protein x 2.7, p less than 0.05; sodium x 1.7, p less than 0.02; bicarbonate x 1.8, p less than 0.05); (c) under conditions of maximal electrical stimulation of the vagus, pancreatic response was unsignificantly increased; (d) dose-response curves to secretin and CCK-PZ were unsignificantly changed. 2. Pancreatic weight was not changed. In the pancreatic tissue: (a) total protein decreased (-10 p. 100, p less than 0.01) as well as amylase (-30 p. 100 p less than 0.001), lipase (-19 p. 100, p less than 0.01) and trypsinogen (-9 p. 100, NS); (b) concentrations of DNA and RNA were unsignificantly increased; (c) histological structure was normal in optical microscopy. 3. Antral gastrin cell numbers were not changed. 4. In conclusion, a decrease in pancreatic enzymatic contents, associated with an increase of total protein in basal secretion and after maximal stimulation by 2DG are consistent with the hypothesis of an increase in synthesis and a decrease in turnover time of exportable proteins in the pancreatic tissue of methadone treated rats. No chronic pancreatitis was observed in these conditions. Endogenous gastrin was probably not involved in pancreatic changes observed.