Disease relevance of Lipf

• Lingual lipase: an important lipase in the digestion of dietary lipids in cystic fibrosis [1]?
• In these patients with severe pancreatic insufficiency, we suggest that the lingual lipase is responsible for a considerable proportion of triglyceride hydrolysis [1].
• Furthermore, l-alphaAAA did not alter the vasodilation elicited by topical application of an acidic artificial cerebrospinal fluid solution, suggesting that the GL influences the pial arteriolar relaxation elicited by hypercapnic, but not local extracellular (EC), acidosis [2].
• In view of a negligible gastric lipase activity in animals with an esophageal fistula and of decreased hydrolysis of a triglyceride test meal, these data suggest that gastric lipolysis is of physiological importance in situations where lipolytic mechanisms are stressed by a large fat intkae [3].
• METHODS: Renal failure was induced by five-sixths nephrectomy (NR), bilateral ureter ligation (BUL), the intramuscular injection of glycerol (GL), and the intraperitoneal injection of cisplatin (CDDP) [4].

High impact information on Lipf

• Rat lingual lipase was purified to homogeneity by solubilization in 1% octylglucoside, followed by centrifugation, affinity chromatography on hydroxylapatite, gel filtration, and chromatofocusing [5].
• 5. This indicates that lingual lipase, which is known to be active in stomach, could act in the small intestines [6].
• The activity of lingual lipase in the presence of sodium taurodeoxycholate and CaCl2 was decreased only 33% when pH of the incubation medium was increased to 6 [6].
• Purified lingual lipase hydrolyzed immediately long chain triacylglycerol to diacylglycerol and fatty acid in medium containing 17 mM sodium taurodeoxycholate and 3.3 mM CaCl2 at pH 5 [6].
• The amino acid sequence of mature rat lingual lipase consists of 377 residues and shares little homology with porcine pancreatic lipase apart from a short region containing a serine residue at an analogous position to the ser 152 of the porcine enzyme [7].

Chemical compound and disease context of Lipf

• PTU-induced delayed maturation of lingual lipase was a result of hypothyroidism, since T4 replacement when given early (at the age of 5 days) abolished most of the effect of PTU [8].
• Tetrahydrolipstatin (THL) derived by hydrogenation from lipstatin, a lipase inhibitor produced by Streptomyces toxytricini, has been shown to inhibit in vitro the activity of all three lipases secreted to the gastro-intestinal tract; gastric lipase, pancreatic lipase and carboxylester lipase (cholesterol ester hydrolase) [9].

Biological context of Lipf

• Molecular cloning and nucleotide sequence of rat lingual lipase cDNA [7].
• Lingual lipase is thought to be an auxiliary enzyme for fat digestion and absorption in mammals; however, the reason for lipolysis in the oral cavity is not known [10].
• Studies on fat digestion, absorption, and transport in the suckling rat. II. Triacylglycerols: molecular species, stereospecific analysis, and specificity of hydrolysis by lingual lipase [11].
• We investigated the substrate specificity of this enzyme as well as the potential of lingual lipase to act in the upper small intestine i.e., in the presence of bile salts and lecithin [12].
• A cDNA library was constructed from mRNA isolated from human stomach tissue and probed with cloned rat lingual lipase DNA [13].

Anatomical context of Lipf

• In contrast, the dorsal GL was disrupted, and Schwann cells were seen within the dorsal funiculus [14].
• The ventral GL of the rat lumbosacral spinal cord is a more substantial structure than the dorsal GL during normal development [14].
• However, our observations suggest that subpial astrocytes of the dorsal GL are more susceptible to radiation damage at three DP than the subpial astrocytes and radial glia of the ventral GL [14].
• This inactivation is not prevented by colipase but is partially averted by lipids and protein, suggesting that lingual lipase can remain active in the duodenum [12].
• A substantial portion of rat milk triglycerides was hydrolyzed in the ligated stomach of suckling rats with excised lingual gland and pancreas, due to the action of gastric lipase [15].

Associations of Lipf with chemical compounds

• Purified rat lingual lipase (EC3113), a glycoprotein of approximate molecular weight 52,000, was used to generate polyclonal antibodies which were able to recognise the denatured and deglycosylated enzyme [7].
• We focused on the gustatory sense and investigated the significance of lingual lipase in the perception of a fat taste by using orlistat, a potent lipase inhibitor [10].
• Radioactive triolein applied on rats' circumvallate papilla revealed that lingual lipase was released continuously to generate significant amounts of fatty acids and other lipolytic products within 1-5 s, which was enough time to taste fat [10].
• The effect of guanethidine was found to be transient, in that the lingual lipase activity showed complete recovery upon withdrawal of the treatment for 1 week [16].
• The results suggest a unique bimodal regulation of lingual lipase by dexamethasone in the rat serous glands [17].

Regulatory relationships of Lipf

• Substance P and somatostatin were identified in cells of the lingual serous glands and may be additional local modulators regulating lingual lipase release [18].

Other interactions of Lipf

• The effect of guanethidine on lingual lipase suppression was not a result of induced stress, since simultaneous treatment with RU-38486, a known glucocorticoid receptor antagonist, did not prevent the decrease in lingual lipase activity [16].
• Propranolol and timolol, beta 1/beta 2-adrenergic receptor antagonists were not effective and the cholinergic receptor antagonist, atropine, was effective in only slightly reducing amylase secretion but not lingual lipase [19].
• Decrease in contents of pancreatic carboxyl ester lipase, phospholipase A2, and lingual lipase in rats with streptozotocin-induced diabetes [20].
• Isoproterenol evoked decreases in alpha-amylase- and Rab3D-labelled parotid secretory granules, and pilocarpine stimulated decreases in secretory granules labelled for lingual lipase and Rab3D from von Ebner's glands, and amylase and Rab3D from pancreas [21].
• The H2 receptor inhibitors, cimetidine and ranitidine, stimulated secretion of only amylase, but not lingual lipase [22].

Analytical, diagnostic and therapeutic context of Lipf

• A similar value for Mr of protein with lipolytic activity was obtained when acetone-precipitated protein was subjected to gel filtration on Sephadex G-200 indicating that 51,000 is the Mr of an active form of lingual lipase [6].
• Adrenalectomy abolished the developmental increase of lingual lipase [17].
• Developmental delay of lingual lipase expression after guanethidine-induced sympathectomy [16].
• When fed by gastric perfusion 5 times (corn oil, 4 g/day) their usual dietary intake of fat, rats deprived of lingual lipase by the creation of an esophageal fistula had a significant degree of fat and bile acid malabsorption as well as a shortened bile acid half-life when compared to animals with a gastrostomy [3].
• Electron microscopy revealed that the only cells containing lingual lipase were the developing serous cells; secretory granules containing lingual lipase of varying degrees of maturity were seen [23].

References