Full resolution (JPEG) - On this page / på denna sida - VIII. Digestion - IV. The Pancreas and Pancreatic Juice
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
502 DIGESTION.
-and glycerin, which is an enzymotic process; and secondly, it has also
the property of emulsifying the fats.
The action of the pancreatic juice in splitting the fats may be shown
in the following way: Shake olive-oil with caustic soda and ether,
siphon off the ether and filter if necessary, then shake the ether repeatedly
with water and evaporate at a gentle heat. In this way is obtained a
residue of fat free from fatty acids, which’ is neutral and which dissolves
in acid-free alcohol and is not colored red by alkanet tincture. If such
fat is mixed with perfectly fresh alkaline pancreatic j uice or with a freshly
prepared infusion of the fresh gland and treated with a little alkali or
with a faintly alkaline glycerin extract of the fresh gland (9 parts glyc-
erin and 1 part 1 per cent soda solution for each gram of the gland),
and some litmus tincture added and the mixture warmed to 37° C,
the alkaline reaction will gradually disappear and an acid one take its
place. This acid reaction depends upon the conversion of the neutral
fats by the enzyme into glycerin and free fatty acids. A very much
used method consists in determining the acidity of the mixture by means
of titration before and after the action of the juice or the infusion.
The action of the pancreatic juice in splitting fats is a process analo-
gous to that of saponification, the neutral fats being decomposed, by
the addition of the elements of water into fatty acids and glycerin
according to the following equation. C3H5.O3.R3 (neutral fat)+3H20 =
C3H5.O3.H3 (glycerin) +3 (H.O.R) (fatty acid). This depends upon
a hydrolytic splitting, which was first positively proved by Bernard
and Berthelot. The pancreas enzyme also decomposes other esters,
just as it does the neutral fats (Nencki, Baas, Loevenhart x
and
others). The fat-splitting action of the lipase is, according to Paw-
low, Bruno and many others 2
aided in its action by the bile. Rosen-
heim and Shaw-Mackenzie found that the lipase action was accel-
erated by ha3molytic substances, as well as by normal serum; this
accelerating action was inhibited by cholesterin. The accelerating
substance of the serum was dialyzable and resistant to heat. Rosen-
heim was able to divide the lipase existing in a glycerin extract of the
pig pancreas into enzyme and co-enzyme (page 52); in diluting with
water a precipitate occurred which contained the real thermolabile
enzyme while the dialyzable, heat resisting co-enzyme remained in the
1
Bernard, Ann. de chim. et physique (3), 25; Berthelot, Jahresber, d. Chem.,
1855, 733; Nencki, Arch. f. exp. Path. u. Pharm., 20; Baas, Zeitschr. f. physiol. Chem.,
14, 416; Loevenhart, Journ. of Biol. Chem., 2; Terroine an 1 Z. Morel, Compt. rend.
80C. biol., 65, 66.
2
Bruno, Arch, des scienc biol. de St. P6tersbourg, 7; see also Loevenhart and
Souder, Journ. of biol. Chem., 2; v. Furth and Schutz, Hofmcister’s Beitrage, 9; Ter-
roine, Bioch. Zeitschr. 23; Compt. rend. soc. biol. 68, 439, 518, 666, 754 (1910).
<< prev. page << föreg. sida << >> nästa sida >> next page >>
