Chemical and microscopic nature of pancreata from chicks fed unheated soybean meal

Effect of the dietary black gram trypsin inhibitory fraction on the pancreatic activity of male albino mice

The effect of raw black gram and black gram trypsin inhibitory fraction on the pancreatic function of male albino mice has been evaluated. Animals were fed autoclaved black gram (Group I), raw black gram (Group II) and autoclaved black gram incorporated with black gram trypsin inhibitory fraction (Group III). Pancreatic total protease, trypsin and amylase activities were elevated significantly in Group II and III animals. Analyses of intestinal contents showed a constant level of total protease activity in all the groups, along with a significant reduction in trypsin level in Groups II and III. Increased U-14C-lysine incorporation in pancreas and an enhanced level of amylase in intestinal contents show the hyperactivity of the pancreas in Groups II and III. Pancreas weights increased in Groups II and III. Pancreatic protein/mg pancreas and RNA/DNA ratio remained constant in all three groups. It is concluded with histological studies that the black gram trypsin inhibitor increased the pancreatic activity of mice by developing the cellular hyperplasia of the pancreas.

Effect of dietary green gram trypsin inhibitor and raw green gram meal (Phaseolus aureus Roxb) on the pancreatic activity in rats

To evaluate the effect of green gram trypsin inhibitor (GGTI) and raw green gram meal (RGG) the experimental animals were fed with the following diets: (i) AGG meal-control (autoclaved green gram meal), (ii) RGG meal and (iii) AGG meal + 1% GGTI. Pancreatic enlargement was observed in rats fed RGG diet and AGG + GGTI diet. Elevated levels of protease and amylase were observed in pancreas. Intestinal contents showed no significant variation in the protease activity, but a significant variation in the amylase activity was evident. Total RNA, DNA and protein content were increased in the pancreas of group II and group III set of animals, suggesting an active proliferation of acinar cells. RNA and DNA content per unit weight of pancreas and the RNA/DNA ratio remained almost constant indicating the hyperplasia. Histological studies revealed hyperplasia of the acinar cells. The results obtained have been discussed.

The effect of long-term feeding of soya-bean flour diets on pancreatic growth in the rat

1. Pancreatic growth was measured in rats by changes in pancreatic weight, nucleic acid content and protein content after feeding diets of heated soya-bean flour (HSF), raw soya-bean flour (RSF), 200 g raw soya-bean flour + 800 g heated soya-bean flour/kg (80 HSF) and 400 g raw soya-bean flour + 600 g heated soya-bean flour/kg (60 HSF) for periods up to 36 weeks. Control rats of comparable age to soya-bean flour-fed rats were continued on rat cubes during the 36-week study. 2. Cube-fed rats remained significantly heavier than rats fed on soya-bean flour diets. Analysis of variance showed rats fed on HSF were significantly heavier than RSF-fed rats and rats fed on 80 HSF significantly heavier than those fed on 60 RSF. 3. Pancreatic indices in HSF-fed rats were similar to comparable control rats. 4. Hypertrophy was found in rats fed on the RSF-containing diets with the extent of enlargement corresponding to the RSH content. Hyperplasia was also found in rats fed on RSF and 60 HSF. 5. The greatest pancreatic growth was seen in RSF-fed rats with all the indices peaking at 8 weeks followed by a decline and then a rise again at 36 weeks. 6. The fall in pancreatic indices in rats fed on RSF for 12 and 24 weeks is most likely an effect of general malnutrition due to the multiple deficiences in amino acids which occur in animals fed on RSF. The rise at 36 weeks may reflect increased body growth or the beginning of adenomatous changes.

A further physiological role for naturally occurring trypsin inhibitors: the evidence for a trophic stimulant of the pancreatic acinar cell

The oral ingestion of naturally occurring purified trypsin inhibitors from soybean, ovomucoid, and bovine pancreas has been demonstrated to be a potent stimulus to pancreatic digestive enzyme synthesis. This effect may be so marked as to lead to impairment of growth in the rat and chicken through the faecal loss of essential amino acids. This is thought to be due to the markedly potentiated secretion of pancreatic digestive enzyme protein overwhelming the normal digestive capacity of the gastrointestinal tract and resulting in a pancreatogenous protein-losing enteropathy. Experimental evidence is presented to suggest that this response to the trypsin inhibitors requires the mediation of the gastrointestinal tract and is independent of vagal innervation to the pancreas. The most satisfactory hypothesis would favour the release of a trophic stimulus from the intestinal mucosa (possibly pancreozymin-cholecystokinin) to the acinar cell of the pancreas in response to the presence of the trypsin inhibitor in the bowel lumen. It is suggested that a primary function of the endogenously secreted pancreatic trypsin inhibitor may be to potentiate enzyme synthesis by the acinar cell, providing an important stimulus for the repletion of the digestive enzymes. Some of the potential physiological and clinical implications of such a mechanism are discussed.