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Cyclic changes of plasma pancreatic polypeptide and pancreatic secretion in fasting dogs
S169
CYCLIC CHANGES OF PLASMA PANCREATIC POLYPEPTIDE AND PANCREATIC SECRETION IN FASTING DOGS. S Naruse*, RF Murphy, SN Joffe and DN Magee*, Departments of *Physiology, Creighton University, Omaha, Nebraska and Surgery, University of Cincinnati Medical Center, Cincinnati, Ohio, U.S.A. Conscious dogs, each with a gastric fistula, Heidenhain pouch and Thomas type of pancreatic fistula, were used. In fasting animals basal pancreatic secretion changed spontaneously with the periodic changes of duodenal motility. The duration of one cycle was about i00 min and the peak of the pancreatic secretion was just ahead of the peak duodenal contractions. Plasma pancreatic polypeptide (PP) concentration changed in phase with these phenomena; 327 ~ 58 (mean + SE, n = 5) at apogee and 201 + 40 pg/ml at perigee. There was a significant positive correlation (r =--0.54, P < 0.001) between pancreatic secretion and plasma PP. The ganglion blocker (pentolinium 20 mg S.C.) abolished these cyclical changes of the gut and of plasma PP. The concentration of PP after pentolinium remained at the perigee level. Intraduodenal infusion of 2% lidocaine at 5 ml/10 min reduced the duodenal motility to the level of the perigee. Peak pancreatic protein secretion was decreased significantly from 201 + 26 mg/10 min to 123 + 14 mg/10 min, but not down to the perigee level (9 + 4 mg/10 min). The cyclical increase of plasma PP was abolished during duodenal anesthetization, but reappeared when the duodenum recovered from anesthesia. These results suggest that the cyclical release of PP is, at least in part, under the control of the intrinsic nervous system in the gut.
PANCREATIC SECRETORY, CIRCULATORY AND METABOLIC ~ E C ~ S OF ~ S I N (NT) AND DUODENAL OLEATE IN THE DOG. SJ Konturek, J Jaworek, M Cieszkowski, M Dobrzanska, J Swierczek. Inst Physiol, Med Acad, Krakow, Poland. NT is released by intestinal fat and inhibits gastric secretion but its action on the pancreas has been little exanined. This study was designed to compare the effects of NT and duodenal oleate on eMocrine and endocrine pancreatic secretion in response to various stimulants and to determine the action of the peptide on pancreatic circulation and oxygen construction. Six conscious dogs with various fistulas were used and gastric and pancreatic secretions as well as plasma gastrin, NT and pancreatic polypeptide (PP) levels were determined before and after ordinary feeding, sham-feeding, duodenal acidification and iv administration of secretin and caerulein. In anesthetized dogs, blood flow to the pancreas was measured with electrcr~gnetic flow meter; the arteriovenous oxygen difference across the pancreatic circulation was determined photcmetrically and oxygen const~ption by the pancreas was calculated. NT given iv in graded doses (0.15-20 pg/kg-h) in fasted dogs, produced a dosedependent stimulation of pancreatic HC03 and enzyme secretion reaching, respectively, about 33% and 94% of secretin and CCK maximum. Duodenal perfusion with sodit~n oleate in graded doses (1-16 ~M/h) resulted in similar peak HC0$ (26%) and enzyme (78%) outputs. The ccrnbination of secretin or duodenal acidification plus NT (i ug/kg-h) or oleate (8 raM/h) caused similar augmentation of both HC0~ and enzyme responses. NT, like oleate, reduced pancreatic responses to sham-feeding or ordinary feeding probably due to reduction in gastric acid secretion. Both NT and oleate increased dose-dependently plasma NT-like activity, the levels achieved with NT being about 2-3 times higher than those obtained with duodenal fat producing equal rate of Dancreatic HC0~ secretion. Duodenal oleate and NT increased significantly plasma PP levels without affecting sert~n gastrin. IA infusion of NT (0.01-1.6 ~g/kg-h) increased dose-dependently the blood flow to the pancreas and oxygen constmlotion reaching at the highest dose of NT, respectively, about 205% and 107% of the control v a l ~ .
CYCLIC CHANGES OF PLASMA PANCREATIC POLYPEPTIDE AND PANCREATIC SECRETION IN FASTING DOGS. S Naruse*, RF Murphy, SN Joffe and DN Magee*, Departments of *Physiology, Creighton University, Omaha, Nebraska and Surgery, University of Cincinnati Medical Center, Cincinnati, Ohio, U.S.A. Conscious dogs, each with a gastric fistula, Heidenhain pouch and Thomas type of pancreatic fistula, were used. In fasting animals basal pancreatic secretion changed spontaneously with the periodic changes of duodenal motility. The duration of one cycle was about i00 min and the peak of the pancreatic secretion was just ahead of the peak duodenal contractions. Plasma pancreatic polypeptide (PP) concentration changed in phase with these phenomena; 327 ~ 58 (mean + SE, n = 5) at apogee and 201 + 40 pg/ml at perigee. There was a significant positive correlation (r =--0.54, P < 0.001) between pancreatic secretion and plasma PP. The ganglion blocker (pentolinium 20 mg S.C.) abolished these cyclical changes of the gut and of plasma PP. The concentration of PP after pentolinium remained at the perigee level. Intraduodenal infusion of 2% lidocaine at 5 ml/10 min reduced the duodenal motility to the level of the perigee. Peak pancreatic protein secretion was decreased significantly from 201 + 26 mg/10 min to 123 + 14 mg/10 min, but not down to the perigee level (9 + 4 mg/10 min). The cyclical increase of plasma PP was abolished during duodenal anesthetization, but reappeared when the duodenum recovered from anesthesia. These results suggest that the cyclical release of PP is, at least in part, under the control of the intrinsic nervous system in the gut.
PANCREATIC SECRETORY, CIRCULATORY AND METABOLIC ~ E C ~ S OF ~ S I N (NT) AND DUODENAL OLEATE IN THE DOG. SJ Konturek, J Jaworek, M Cieszkowski, M Dobrzanska, J Swierczek. Inst Physiol, Med Acad, Krakow, Poland. NT is released by intestinal fat and inhibits gastric secretion but its action on the pancreas has been little exanined. This study was designed to compare the effects of NT and duodenal oleate on eMocrine and endocrine pancreatic secretion in response to various stimulants and to determine the action of the peptide on pancreatic circulation and oxygen construction. Six conscious dogs with various fistulas were used and gastric and pancreatic secretions as well as plasma gastrin, NT and pancreatic polypeptide (PP) levels were determined before and after ordinary feeding, sham-feeding, duodenal acidification and iv administration of secretin and caerulein. In anesthetized dogs, blood flow to the pancreas was measured with electrcr~gnetic flow meter; the arteriovenous oxygen difference across the pancreatic circulation was determined photcmetrically and oxygen const~ption by the pancreas was calculated. NT given iv in graded doses (0.15-20 pg/kg-h) in fasted dogs, produced a dosedependent stimulation of pancreatic HC03 and enzyme secretion reaching, respectively, about 33% and 94% of secretin and CCK maximum. Duodenal perfusion with sodit~n oleate in graded doses (1-16 ~M/h) resulted in similar peak HC0$ (26%) and enzyme (78%) outputs. The ccrnbination of secretin or duodenal acidification plus NT (i ug/kg-h) or oleate (8 raM/h) caused similar augmentation of both HC0~ and enzyme responses. NT, like oleate, reduced pancreatic responses to sham-feeding or ordinary feeding probably due to reduction in gastric acid secretion. Both NT and oleate increased dose-dependently plasma NT-like activity, the levels achieved with NT being about 2-3 times higher than those obtained with duodenal fat producing equal rate of Dancreatic HC0~ secretion. Duodenal oleate and NT increased significantly plasma PP levels without affecting sert~n gastrin. IA infusion of NT (0.01-1.6 ~g/kg-h) increased dose-dependently the blood flow to the pancreas and oxygen constmlotion reaching at the highest dose of NT, respectively, about 205% and 107% of the control v a l ~ .