Stability of lingual lipase in vivo: studies of the iodinated enzyme in the rat stomach and duodenum.
In order to examine the stability of purified lingual lipase (EC 3.1.1.3) in vivo under fasted and fed conditions, we iodinated rat lingual lipase to a specific activity of 5-10 microCi/micrograms protein with 125I-labelled Bolton-Hunter reagent. Labelled lingual lipase in either saline or Intralipid was administered via an intragastric or intraduodenal cannula. Control labelled lipase preparations were incubated at 37 degrees C. Serial aliquots of gastric or intestinal contents were aspirated and subjected to SDS-polyacrylamide gel electrophoresis followed by autoradiography, and quantitated by densitometric scanning. In all experiments, the amount of lingual lipase in both stomach and duodenum was significantly reduced (P less than 0.05 vs. controls) at 15 and 60 min after administration. In either the presence or absence of Intralipid, lingual lipase was more stable in the stomach than in the duodenum (P less than 0.05). In conclusion, lingual lipase was more stable in the stomach than in the duodenum, and lipid emulsion did not appreciably affect the stability of the enzyme in either location of the upper digestive tract of the rat.
Roberts
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Department of Medicine, George Washington University Medical Center, George Washington University School of Medicine, Washington, DC 20037.
Hanel
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SI
D000818:Animals; D004355:Drug Stability; D004386:Duodenum / Q000201:enzymology*; D005750:Gastric Juice / Q000032:analysis; D007441:Intubation, Gastrointestinal; D007457:Iodine Radioisotopes; D008049:Lipase / Q000008:administration & dosage / Q000032:analysis*; D051381:Rats; D013270:Stomach / Q000201:enzymology*
D007457:Iodine Radioisotopes; D008049:Lipase