The Effect on the Intestine of Intravenous Saline Infusions.
It has been frequently observed that a quantity of fluid enters the
intestine during the intravenous injection of normal salt solution.
According to Dastre and Loye,[62] the fluid injected into the veins
is largely eliminated by the kidneys, although these organs may be
assisted in this function by the salivary glands and intestine. These
authors have found fluid to be present in the intestine of rabbits as
well as in the pleural and peritoneal cavities after the injection
of large quantities of salt solution. They state that in such an
intravenous injection diarrhœa often results which may be so pronounced
that a clear fluid emerges from the rectum. Knoll[63] also mentions the
production of diarrhœa by the injection of large quantities of NaCl
solution.
Magnus[64] in his work on the production of oedema of the skin by
intravenous infusions of salt solutions shows in his tables that a
certain amount of fluid is eliminated by the intestines after the
kidneys have been removed. A rabbit with both kidneys removed was
infused with 1,500 c.c. normal salt solution; 200 g. were eliminated
by the intestine. In a second rabbit 1,010 c.c. of fluid were injected
into the veins and 60 g. were eliminated by the intestine. In a dog
1,760 c.c. were injected and 160 g. eliminated by the intestine.
I have made a number of experiments[65] in which the amount of fluid
passing into the intestine during the intravenous injection of large
quantities of NaCl solution was determined not only when the kidneys
were removed from the circulation, but also when they were active. As
shown by the following experiments, the fluid secreted by the intestine
increases rapidly when m/8 or m/6 NaCl solution is injected into
the blood. Without such an injection or other stimulus very little
intestinal juice can be gathered in a time as short as that occupied by
the experiments. In a rabbit’s small intestine there is usually found
between 5 and 10 c.c. fluid, often much less.
Exp. 1. Rabbit. The bloodvessels to the kidneys were tied off and two
cannulæ were put into the intestine, one 35 cm. from the pylorus and
the other in the lower part of the ileum. Each loop was isolated by
ligatures. The upper one was about 30 cm. long and the lower one 42
cm. The upper loop in the beginning contained 5 c.c. fluid, which were
removed. The lower loop was empty. During the first hour 100 c.c. m/8
NaCl were forced into the blood and 5.2 c.c. fluid appeared in the
upper loop and nothing in the lower loop. During the second hour 240
c.c. NaCl solution were injected and 5.4 c.c. fluid appeared in the
upper loop and 13.6 c.c. in the lower loop. During the third hour 160
c.c. NaCl solution were introduced; 6.6 c.c. fluid appeared in the
upper loop and 15.5 c.c. in the lower. The infusion was then stopped
and 26 c.c. were found in the part of the small intestine not included
in the loops. The total amount thus secreted by the intestine in three
hours was 72.3 c.c. This is 14.46% of the quantity injected.
Exp. 2. In another rabbit with kidneys removed, 470 c.c. NaCl solution
were injected during three hours, and 78 c.c. fluid obtained from the
intestine, which is about 16.6% of the quantity injected.
Exp. 3. In a rabbit in which the kidneys were left intact, 547 c.c. m/6
NaCl solution were injected into the blood. 49.5 c.c. were secreted in
3 hours and 30 minutes by the intestine. This is about 9% of the total
quantity of fluid. The quantity of fluid secreted into the loop in the
first half hour was 1.8 c.c.; in the third half hour, 2.9 c.c.; in the
fifth half hour, 6.6 c.c.
Exp. 4. In a second rabbit in which the kidneys were untouched, the
quantity of m/8 NaCl solution introduced was 390 c.c.; about 40 c.c.
of fluid were obtained during three hours from the intestine. This is
10.25% of the amount injected. In the first hour 5 c.c. were secreted
into the loop; in the second hour 7 c.c.; and in the third hour 11.1
c.c. In the rest of the small intestine 17 c.c. were found.
It is clear from these experiments that a considerable proportion of
the fluid injected in this way is eliminated by the intestine. The
quantity is somewhat greater if the kidneys are extirpated. There is,
however, a limit to the amount that can be excreted by the intestine,
and never, as in the case of the kidney, does the amount excreted
approximate the amount injected. The action of such infusions on the
intestine is nevertheless quite similar to that on the kidneys, and
in many other ways the intestine may be regarded as an excretory
organ which can to some extent take on the functions of the kidney.
The intestinal juice contains many substances contained by the urine.
Among the more conspicuous of these is urea, which was shown by Claude
Bernard[66] to be excreted into the intestine as well as the stomach.
He found that it is readily broken up in the intestinal juice, so that
in many cases only salts of ammonia remain.
Pregl[67] demonstrated the presence of urea in the intestinal juice
of the sheep. He found its concentration there to be 0.248%. In the
intestinal juice of rabbits I[68] have found that small quantities of
urea exist both before and after extirpation of the kidneys. It is
present not only in the normal intestinal juice, but also in the fluid
obtained from the intestine after the infusion of large quantities of
m/6 NaCl. Weintrand[69] has demonstrated uric acid in the intestinal
juice.
_Secretion of sugar into the intestine._ Another instance of the way
in which the intestine can to some extent take up the function of the
kidney is shown by the secretion of sugar by the gut following the
injection of large quantities of normal salt solution. It was shown by
Bock and Hoffmann[70] that the injection of 1% NaCl solution into the
circulation of a rabbit caused transient glycosuria. Large quantities
of the solution were injected at the rate of 25-30 c.c. each 5 minutes,
and the glycosuria appeared in from 20 minutes to 1 hour and 30 minutes
after the beginning of the infusion. After a number of hours (6-7) the
glycosuria diminished in their experiments and finally disappeared,
although the infusion of salt and the flow of urine continued. They
found that the entire quantity of sugar eliminated was in one case
1.632 g., and in another case 2.04 g. The percentage of sugar in the
urine reached 0.136 and 0.219 respectively in the two experiments.
These facts were confirmed by Külz,[71] who found also that section
of the splanchnics prevented the glycosuria. The experiments lately
published by M. H. Fischer[72] show that the glycosuria is caused not
only by NaCl, but by certain of the salts which were shown by Loeb[73]
to produce muscular twitchings. He further showed that calcium has the
power of suppressing the glycosuria.
This secretion of sugar by the kidneys following intravenous infusions,
together with the facts shown above that fluid is eliminated to some
extent by the intestine in the absence of the kidneys, led me to
inquire whether the intestine also secretes sugar when the kidneys have
been extirpated and a large amount of NaCl solution is injected. A
number of experiments were made to determine this. I have found[74] in
brief that with the infusion of large quantities of m/6 NaCl solution
into the circulation sugar is abundantly secreted into the intestine.
This takes place not only when the kidneys are removed, but also when
they are intact, and are also eliminating sugar. This may be seen in
the following tables:--
Rabbit--Blood vessels of kidney ligatured; cannula in upper part of
small intestine, with loop 35 cm. tied off. Loop emptied; contents 5
c.c., which contained no sugar.
NaCl m/6 Intestinal Sugar examination of
Time injected juice intestinal juice
10:00 Infusion begun Loop emptied, No sugar
5 c.c.
10:30 20 c.c. 3 c.c. No sugar
11:00 40 c.c. 3 c.c. No sugar
11:30 20 c.c. 4 c.c. No sugar
12:00 120 c.c. 6 c.c. Trace of sugar
12:30 200 c.c. 12 c.c. Sugar abundant
1:00 --c.c. 28 c.c. Sugar abundant
--------
400 c.c.
Here the sugar appeared in the intestinal juice after about 200 c.c.
NaCl solution had been injected. The injection was made in each case
into the vein of the ear by means of a pressure bottle connected with
the water tap. The pressure bottle was in turn connected with a bottle
holding the solution, which was thus forced out at a constant rate
through a long rubber tube immersed in water at 40° C. A hypodermic
needle was fastened in the end of this tube and inserted into the
marginal vein of the rabbit’s ear. In this way the quantity of fluid
injected could be accurately measured and controlled. The salt solution
after passing through the long tube reached the ear at approximately
body temperature. It is of the greatest importance to protect the
intestinal loops in every way possible from loss of heat or from drying.
In the above experiment the _intestinal glycosuria_, if such a term may
be applied to this phenomenon, appears under circumstances which are
exactly the same as those necessary for the production of sugar in the
urine by saline infusions. A further example of this is shown in the
following experiment:--
Rabbit--Blood vessels of both kidneys ligatured. Intestinal loop
including duodenum 32 cm. long. In the loop were found 3 c.c. fluid
which contained no sugar.
NaCl m/6 Intestinal Sugar examination of
Time injected juice intestinal juice
9:45 Infusion begun Loop emptied, No sugar
3 c.c.
10:15 10 c.c. 3 c.c. No sugar
10:45 70 c.c. 3 c.c. No sugar
11:15 75 c.c. 3.2 c.c. No sugar
11:45 85 c.c. 5 c.c. Sugar abundant } 0.202%
} 0.222%
12:15 80 c.c. 9.5 c.c. Sugar abundant 0.25%
12:45 150 c.c. 21 c.c. Sugar abundant
--------
470 c.c.
Here the sugar appeared after the infusion of about 240 c.c. NaCl
solution. The experiment was not carried on to see how long the sugar
would continue to be present in the intestinal juice. The animal
was killed, and it was found that the remaining loops of the small
intestine held 32 c.c. of fluid which contained sugar. The stomach
contents included about 40 c.c. fluid which also contained sugar. Of
the 470 c.c. of fluid injected, 78.7 c.c. were eliminated by the small
intestine and 40 by the stomach. The alimentary canal, then, exclusive
of the large intestine, eliminated about 118 c.c. of the fluid
introduced, which is approximately 25%.
Quantitative estimations of the sugar in the intestinal juice in
this case were made. The amount varied between 0.2 and 0.3%. I have
not attempted to ascertain the total quantity of sugar which may be
obtained from the intestinal juice by continued infusion of salt
solution. In the case of the urine, Bock and Hoffmann made such
determinations and found that the kidney eliminated in one case 1.632
g. and in another case 2.04 g. sugar. M. H. Fischer found that the
concentration of sugar in the urine of a rabbit rarely exceeds 0.25%
after infusion of m/6 NaCl.
Thus the intestine eliminates sugar in a way that entirely resembles
its elimination by the kidneys. The sugar appears in the blood after
the infusion of a certain amount of the salt solution and is excreted
by the kidney. If the kidneys are removed, it is excreted by the
intestine. But even when the kidneys are intact there is a certain
amount of sugar excreted by the intestine, just as a part of the fluid
injected is eliminated by the intestine when the kidneys are still
active. As shown in the following experiment, the sugar appears both in
the intestinal juice and in the urine. The quantity of sugar, however,
is greater in the urine than in the intestinal juice. In the urine it
was found to be about 0.2%, in the intestinal juice considerably less.
The quantity of urine also is greater than the quantity of intestinal
juice. Therefore the greater proportion of the sugar is excreted by the
kidneys.
Rabbit--Cannula placed in bladder. Kidneys intact. Cannula in loop of
upper part of small intestine 35 cm. long. Loop contained 4.2 c.c.
fluid; no sugar.
Intestinal juice. Urine.
NaCl m/6 /---------------------\/----------------------\
Time. injected. Quantity. Sugar Quantity. Sugar
examination. examination.
9:45 Infusion Loop emp’d, No sugar. Bladder No sugar.
begun. 4.2 c.c. emptied, 5 c.c.
10:15 5 c.c. 1.8 c.c. ” ” 0.0
10:45 50 ” 2.2 ” ” ” 0.0
11:15 80 ” 2.9 ” ” ” 4.0 c.c. No sugar.
11:45 92 ” 3.8 ” ” ” 15.0 Sugar present.
12:15 120 ” 6.6 ” Sugar present. 38.0 Much sugar.
12:45 150 ” 7.8 ” ” ” 40.0 ” ”
-----
497 ”
It is interesting to note in connection with these experiments the
secretion of sugar into the stomach which followed the intravenous
infusion of NaCl solution. Ordinarily in the normal rabbit only a very
small quantity of fluid can be obtained from the stomach. This was
not found in my experiments to contain sugar. In one case after the
infusion of 470 c.c. NaCl solution the stomach contained about 40 c.c.
of fluid. In a second instance 32.8 c.c. of fluid were secreted by the
stomach during 2 hours and 30 minutes, during which time 390 c.c. NaCl
solution were injected. In both these experiments sugar, which was not
present in the beginning, appeared in considerable quantities after the
infusion had continued for a little time. Thus the stomach excretes
sugar under circumstances similar to those under which it is excreted
by the intestine. Claude Bernard[75] describes the presence of sugar in
the gastric contents of diabetic patients. He quotes McGregor as having
made the observation by causing patients to vomit. On examination of
the gastric contents sugar was demonstrated. It seems possible that in
this case the food might have contained a reducing substance.
Thus a study of the effect of saline infusions on the intestine leads
us to the idea of the alimentary canal as in some sense a subsidiary
excretory organ. In addition to its other better known functions, the
intestine can to some extent take on some of the functions of the
kidney. As shown above, it not only tends to eliminate an excess of
fluid forced into the circulation, but also excretes urea and uric
acid. Further, under circumstances which cause glycosuria, sugar is
also excreted by the intestine.
FOOTNOTES:
[62] Arch. de physiol. norm. et path., 4 e série, 2, 1888, p. 93; 5 e
série, 1, 1889, p. 253.
[63] Arch. für exp. Path. u. Pharm., Bd. XXXVI, S. 293, 1895.
[64] Arch. für exp. Path. u. Pharm., Bd. XLII, S. 250, 1899.
[65] MACCALLUM, J. B.: University of California Publications,
Physiology, Vol. I, 1904, p. 125.
[66] Leçons sur les propriétés physiologiques et les altérations
pathologiques des liquides de l’organisme, II Tome, Paris, 1859.
Deuxième Leçon.
[67] Archiv für die gesammte Physiologie, Bd. 61, 1895, p. 378.
[68] _Loc. cit._
[69] Chemische Centralblatt, Leipzig, Bd. II, 1895, S. 310.
[70] BOCK and HOFFMANN: Arch. für Anat., Physiol. und wissenschaftl.
Med. (Reichert und DuBois-Reymond), p. 550, 1871.
[71] KÜLZ: C. Eckhard’s Beiträge, Bd. 6, S. 117, 1872. (Quoted by
Pflüger, Arch. für die gesammte Physiologie, Bd. 96, 1903, S. 313.)
[72] M. H. FISCHER: University of California Publications, Physiology,
Vol. I, pp. 77 and 87, 1904.
[73] LOEB, J.: Festschrift für Fick, 1899; Pflüger’s Archiv, 1902, XCI,
p. 248.
[74] MACCALLUM, J. B.: University of California Publications,
Physiology, Vol. I, 1904, p. 125.
[75] Leçons sur les propriétés physiologiques des liquides de
l’organisme, T. II, 1859, p. 74.