[Gastric lipolysis in the young rabbit: origin and physiological importance of the lipase].

1. Lipolytic activity of pregastric and gastric secretions and extracts of the gastric wall of weaned and non weaned rabbit was measured in vitro on several substrates: lipids from rabbit and cow milk or from several lipid emulsions (triglycerides containing 3 identical chains, medium or long; coconut or sunflower oil; fats extracted from rabbit or cow milk). Only extracts and gastric secretions possess a lipolytic activity. This persists without attenuation if the pancreatic duct is ligatured. It is reduced after weaning. 2. This lipolytic activity evolves in the presence of high concentration of serum albumin (3%). In this case its optimal pH is 7. Its action preferentially liberates medium chain fatty acids, and, amongst long chain fatty acids, the unsaturated one. Sodium taurocholate (6 mM) slightly increases its effect, which remain unchanged after preincubation of gastric extracts or secretions at pH greater than 2.6. These results show that a gastric lipase exists in the young rabbit. 3. The differences observed between the conditions of activity of young rabbit gastric lipase, pregastric esterase or lipase of man, calf and rat and pancreatic lipase are discussed. We suggest the probable importance of gastric lipase in the particular way and means of digestion and absorption of the lipids of maternal milk in the young rabbit.