Pharyngeal lipase and digestion of dietary triglyceride in man.

Abstract

A B S T R A C T Lipolytic activity was studied in esophageal and gastric aspirates obtained with a nasogastric tube from 14 healthy adult subjects. Samples were collected from esophagus, first at 30-35 cm and then at 40-45 cm from the nose, as the subject, after drinking 15-30 ml of a cream-milk mixture, swallowed small amounts of water. The samples from stomach were taken last and usually contained a small amount of cream-milk mixture. Lipolytic activity was assayed using chylomicron, milk, and corn oil triglyceride as substrate. Esophageal and gastric samples both contained lipolytic activity which hydrolyzed long-chain triglyceride to diglyceride, monoglyceride, and FFA, had a pH optimum of 5.4, and was not affected by either 0.5 M NaCl or 4 mM sodium taurodeoxycholate. The activity, expressed as nanomoles of chylomicron triglyceride hydrolyzed per milliliter per minute, ranged from 0 to 145 in upper esophageal, 5 to 303 in lower esophageal, and 50 to 357 in gastric samples. Only a trace of lipolytic activity was found at pH 5.4 in saliva collected from the parotid, submandibular, and sublingual glands, thus excluding those tissues as a source of the activity found in esophageal and gastric aspirates. The findings suggest that in man glands in or near the pharynx secrete a lipase that acts in the stomach to hydrolyze long-chain triglyceride to partial glycerides and FFA. It is proposed that this reaction is the first step in the digestion of dietary fat and that the amphi-

N‐Butyl‐N‐methyl‐4‐nitrophenyl carbamate as a specific active site titrator of bile‐salt‐dependent lipases

“…Sodium taurocholate, sodium deoxycholate and acetyl choline chloride were from Calbiochem and Fluka respectively. Bile-salt-dependent lipase was purified from human skimmed milk or from human and dog pancreatic juice using an immunoaffinity column [3 11. Human pancreatic colipasedependent lipase was purified according to De Caro et al.…”

“…These are the bile-salt-dependent lipase (cholesterol esterase) [I], the pancreatic colipase-dependent lipase [2] and the preduodenal acid lipase [3]. Bile-salt-dependent lipase originating from milk or pancreatic juice [4] presents a wide substrate specificity, since it has been shown to be involved in dietary hydrolysis of triacylglycerol esters, cholesterol esters and lipid-soluble vitamin esters [l, 51.…”

Les lipases du tractus digestif

“…Dès les premiers travaux, qui remontent au début du siècle, l'activité lipase trouvée au niveau de l'estomac fut dénommée lipase gastrique (Volhard, 1901 ;Schonheyder et Volquartz, 1946). Plus tard, l'activité lipasique principale fut attribuée chez l'homme à un enzyme de la sécrétion des glandes de von Ebner, localisées dans la partie postérieure de la langue ; cet enzyme fut dénommé lipase linguale, par analogie avec la lipase linguale de rat (Hamosh et al, 1975 ;Sterling, 1954 ;Jensen et al, 1982 ;Hamosh, 1979 ;Hamosh et al, 1981 (Hamosh, 1984 (Hamosh, 1984 ;Verger, 1984).…”

“…1 (De Caro et al, 1981, Verger, 1984 Les différences dans la résistance à la dénaturation interfaciale de lipases d'origines diverses peuvent permettre d'expliquer les effets opposés des amphiphiles sur l'activité de l'enzyme gastrique par rapport à l'enzyme pancréatique (Gargouri et al, 1983(Gargouri et al, , 1984a(Gargouri et al, , 1984b(Gargouri et al, , 1986aKlein et al, 1967 ;Patton et Carey, 19811. (Hamosh, 1984, Muller et al, 1975 (Gargouri et al, 1984a (Gargouri et a/., 1986b). Il est actuellement admis que la lipolyse intragastrique génère principalement des acides gras libres et des diglycérides (Hamosh et al, 1975(Hamosh et al, , 1978 (Hamosh et al, 1975(Hamosh et al, , 1978. Il semble donc que, dans ces conditions, la préhydrolyse gastrique génère un substrat directement hydrolysable dans l'intestin par la lipase pancréatique.…”

Intestinal absorption of triglycerols

“…The phospholipids in chylomicrons are mainly of endogenous origin ; the cholesterol derives from many sources (diet, blood, digestive secretions, new (Hamosh and Scow, 1973 ;Hamosh et al, 1975) Rozier, 1947, 1948 ;Desnuelle, Naudet and Constantin, 1951 ;Savary and Desnuelle, 1956), Mattson and his collaborators (Mattson et al, 1952 ;Beck, 1955, 1956 ;Mattson and Volpenhein, 1968), and Borgstrbm (1952a, b ; 1953a, b ; 1954a, b Clement and Bezard, 1962). Lipase activity according to the triglyceride fatty acid structure (double-bond localization, branched polyenoic acids, chain longer than 18 C) has been studied by Brockerhoff (1970 (Favarger, 1958(Favarger, , 1960Bennett, 1964 ;Vodovar et al, 1965).…”