Weaning and feed intake alter pancreatic enzyme activities and corresponding mRNA levels in 7-d-old piglets.

We investigated the changes in the capacity for synthesis of the exocrine pancreas of piglets during the 2 wk after weaning at 7 d of age (trial 1) by measuring the expression of digestive enzymes at mRNA and activity levels in pancreas homogenates, and the effects of high and low feed intakes during the 1st wk postweaning (trial 2) on these measures. The trypsin mRNA level was transiently decreased 43% 3 d postweaning (P < 0.05). Thereafter, trypsin and lipase mRNAs linearly increased (P < 0.05). During the 1st wk postweaning, trypsin- and lipase-specific activities were reduced 44 and 79% (P < 0.05), respectively, whereas 14 d after weaning, trypsin was at the preweaning value and lipase was at a low level. Amylase-specific activity did not change with weaning. Plasma cholecystokinin (CCK) and gastrin concentrations decreased 1 d postweaning and increased afterward up to 3 and 5 d postweaning, respectively. By 3 d after weaning, the mRNA level of trypsin was twofold higher (P < 0.05) in piglets that consumed more feed than in those that consumed less, whereas 7 d after weaning, the groups did not differ. By 7 d after weaning, the specific activity of amylase was higher, and lipase-specific activity was lower, in piglets that consumed more feed than in those that consumed less. Plasma CCK and gastrin concentrations measured 7 d after weaning were correlated with feed intake (r = +0.56 and r = +0.68, P < 0.05, respectively). In conclusion, by 3 d postweaning, pancreatic exocrine function was adapting to the new diet. Afterward, the expression of specific genes coding digestive enzymes and the levels of pancreatic enzyme activities were restored or stimulated, except for lipase-specific activity. Therefore, the pancreas can adjust to weaning and dry food intake as early as wk 2 of life.

[Preparation and properties of pancreatin immobilized on carboxymethylcellulose]. / Poluchenie i svoistva pankreatina, immobilizovannogo na karboksimetiltselliuloze.

A method for immobilizing pancreation on carboxymethylcellulose (CMC) is proposed. The optimum reaction conditions were determined: CMC, 1 x 10(-4) M; 1-ethyl 3-(dimethylaminopropyl)-carbodiimide, 2 x 10(-4) M; incubation time, 18 h at 4 degrees C. They allow obtaining a conjugate of the enzyme with the polymer displaying 85% of the protease and 92% of the esterase activity. Both the native and immobilized enzymes were shown to contain thermolabile and thermostable fractions with different inactivation constants. Immobilization of the enzyme was found to increase its thermal stability by a factor of 1.5 to 3. Thermodynamic constants of blood protein hydrolysis by native and immobilized enzymes were determined.

Influence of environmental conditions on exocrine pancreatic response to intravenous injection of ethanol or 2-deoxyglucose in the dog.

When dogs have free access to the outside, an intravenous injection of ethanol depresses secretin-stimulated exocrine pancreatic secretion by a vagally mediated mechanism. This was shown in two separate series of six and seven dogs each. When dogs were kept in air-conditioned windowless kennels, the response to a meal was unchanged but the response to ethanol was reversed to stimulation. In four dogs, ethanol 1 g/kg was given during a secretin infusion. Three months after changing from open to closed kennels the inhibition (-86% for protein output) was still present, but after 6 months ethanol produced a stimulation (+62%) of pancreatic secretion. This increase was abolished, but not reversed, by keeping the animals outside during the day for four weeks, whereas after three months there was a partial restoration of the inhibitory effect (-39%). In contrast, changing from an open to a closed kennel changed the initial response to 2-deoxy-D-glucose (2-DG), 100 mg/kg, from stimulation to inhibition. These results suggest that environmental conditions affect the cranial regulation of pancreatic secretion.