Lipase and Pepsin Activities in the Stomach Mucosa of the Suckling Dog

Abstract

The origin of preduodenal lipases was investigated in the suckling dog. In this species, gastric lipase is the main (or only) preduodenal lipase (activity range 1.03–8.32 U/mg protein), lingual-lipase activity being absent or amounting to traces only (0.77–2.3 mU/mg tissue). The localization of lipase activity in the stomach was mapped and compared to that of pepsin. The data show that the highest lipase activity was found in biopsy specimens of gastric mucosa from the cardia area (5.32 ± 1.29–8.32 ± 0.93 U/mg protein), and the lowest in the antrum (1.03 ± 0.16–1.94 ± 0.43 U/mg protein). Activity was also significantly higher in the mucosa along the greater rather than the lesser curvature of the stomach. Pepsin activity was highest in the cardia and gastric body areas (26.2 ± 0.89–89 ± 23.61 and 26.83 ± 15.98–69.51 ± 9.82, respectively). Contrary to lipase activity, considerable pepsin activity was present in the antrum (18.17 ± 4.12–23.07 ± 5.60 U/mg protein). No difference in pepsin activities was found in the greater as compared to the lesser curvature. The data show similar origin and tissue distribution of gastric digestive enzymes in the suckling dog and human infant. The role of the newborn dog as an animal model for fat digestion in the human infant is discussed.

Activities of gastric, pancreatic, and intestinal brush-border membrane enzymes during postnatal development of dogs

“…28 These findings, in conjunction with the low activities of trypsin in luminal contents, suggest that newborn dogs have only limited abilities to hydrolyze dietary protein. The combination of low pH of the stomach contents of the dogs reported here, high protease activities in the gastric mucosa of neonatal dogs 29 and pigs, 27 high trypsin activity in pancreatic tissue, and enteropeptidase activity in the proximal region of the small intestine of the dogs of this study indicate that low luminal proteolytic activity during the perinatal period is limited by secretion, not by synthesis or activation. Similarly, peptidase activity associated with the BBM was lower for neonatal puppies, compared with activity for older puppies or adult dogs.…”

“…Although lingual lipase is secreted by suckling rats, 54 the potential contribution to lipid digestion is unknown for suckling puppies and is minimal or lacking for adult dogs. 29 The shift to a greater dependency on pancreatic lipase between the suckling period and adulthood was evident by the > 1,000-fold increase for the lipase-to-trypsin ratio in the luminal contents of the small intestine.…”

“…51 Colostrum has lower lipase activity, compared with the activity for milk, and this is consistent with the lower activity measured in the contents of the stomach and small intestine at day 1, compared with activity measured at day 21. Lipase is also secreted by the gastric mucosa of suckling dogs 29,52 and cats, 53 and 10 to 30% of milk fat is hydrolyzed in the stomach of suckling rats. 54 Gastric lipases can be differentiated from those secreted by the pancreas on the basis of stereospecificity 55 and optimal pH.…”

Histochemical Demonstration of Lipase Activity in the Gastric Mucosa of the Cat

“…In contrast, lipase activity is present in specific areas of the stomach in other species. For example in the stomach of humans, dogs and rabbits lipase is produced mainly in the cardiac region (DiPalma et al, 1991;Kirk et al, 1991).…”

Gastric Lipase and Pepsin Activities in the Developing Ferret: Nonparallel Development of the Two Gastric Digestive Enzymes

“…The activity of gastric or lingual lipase (almost identical enzymes produced at different sites in various species (4) but acting in the stomach) has been quantified in the rat(5‐7), dog (8), ruminants(9,10), and infants(11,12), and the extent of gastric digestion of milk fat has been reported to be in the range of 20% to 50%(7,10,11,13,14). Pepsin activity was studied during early fetal development (15); however, much less is known about the activity level of pepsin during late fetal development (14‐16,17), except that activity is generally very low in the newborn(14,17).…”