Experimental Study on Lipid Metabolism of the Lung in Rats Administrated Various Kinds of

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Acta med . nagasaki ; 237 —256

Experimental Study on Lipid Metabolism of the Lung in Rats Administrated Various Kinds of

Fats and Oils

Genichiro MAMEYA *

Second Departement of Internal Medicine,

Nagasaki University School of Medicine,

Nagasaki, Japan

Received for Publication February 20, 1967

Wistar male rats were administrated Various Kinds of fats orally by a stomach tube, and each lipid content and fatty acid composition of each

lipid fraction in the lung and liver were measured at time intervals of 3, 6

and 9 hours after administration. Both lung and liver showed increase of each lipid content, especially that of phospholipid content, 6 hours after

the administration of safflower oil and trilinolein. In the fatty acid com-

position of the simple lipid fraction, increase of linoleic acid was recogni-

zed, and in the fatty acid compoition of the phospholipid fraction, increase

of linoleic and arachidonic acids. From this fact, it is considered that the

conversion of linoleic acid into arachidonic acid takes place in the lung as

weel as in the liver. After the administration of safflower oil, any marked

change could not be recognized in the lipid composition and the fatty acid

composition of each fraction in the heart, kidney and spleen. After the

administration of fats, the lipoprotein lipase (LPL) activity of the lung was

enhanced in an earlier time than that of plasma, and lowered afterward.

Following this change, each lipid content of the lung showed increase earli- er than that of liver, and decrease afterward. From this fact it is sugges-

ted that the lung reacts to the exogenous fats as well as the liver, and in

an earlier time, produces LPL, hydrolyzing the fats and incorporating the

hydrolyzed fats to cope with alimentary hyperlipemia.

INTRODUCTION

It has been considered that the lung is an organ which performs external respiration, and many studies have been reported on its res- piratory function, but few studies have made on its respiratory func- tion, but few studies have been made on its metabolism. Concerning the lipid metabolism of lung, SIEBER and SAxL,"2) reported for the

*豆谷源一郎

237

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G . MAMEYA

first time half a century ago, and later ROGER and BINET,3)4) reported that the lung has a function to take up and hydrolyze triglycerides in the circulating blood. Ever since this problem has been left unnoticed and some later investigators on this subject failed to confirm the pre‑

viously reported results.5)6)7) But the absorption pathway of lipid in vivo is different from that of protein or glucose: the fats administrated orally are absor'bed by the intestine, sent, for the most part, through the thoracic duct, taken up into the blood stream as chylomicron, and carried to the lung which is the first substantial organ for the fats to pass through. These physio‑anatomical characterisitics suggest that the lung has a special relation to lipid metabolism. By using isotope‑

labeled fatty acids the absorption pathway of lipid was clarified and it was realized that the fatty acids with less than 10 carbons mainly get into the portal vein, and the high‑class fatty acids with more than 12 carbons, especially more than 16 carbons, mostly pass through the

thoracic duct.8)9)lo)11)

S HRADE12) has reported that in the rats orally administrated olive oil, the lipid content of the lung showed a remarkable increase, espe‑

cially the phospholipid content, compared with the unadministrated group. However, KLUGE and SCHMIDT13) has reported that they could not observe any significant change in the total lipid content in the

lung of the administrated group. .

Recently, it was recognized that the lung tissue has lipolytic acti‑

vity in vitr014)15)16) and contains an enzyme which participates in oxi‑

dization and synthesis of fatty acids.17)18) Also it is clinically known that pulmonary tuberculosis is often accompanied by fatty liver,19) and some reports have been made on the occurence of lipoid pneumonia in patients with pulmonary cancer or tuberculosis.20)21)

To elucidate the function of the lung re]ated to the exogenous fat, the author administrated rats various kinds of fats orally and studied the changes of the lipid contents in the lung after the administration of fat, compared with those in the other organs.

EXPERIMENTAL METHOD'S AND MATERIALS

(1) Experiment I

The animals empoloyed were male albino rats of the Wistar strain weighing 160g to 260 g and fed on Oriental chow. After fasting for 12 hours, 5 rats in each group were orally administrated six kinds of fats and oils (group I : safflower oil, group 11 : olive oil, group 111 : beef tallow, group IV : coconut oil, group V : sesame oil, and group VI : butter) by a stomach tube. In group I the animals were exsanguina‑

ted at time intervals of 3, 6 and 9 hours under Nembutal anesthesia.

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1967

The

given

fatty acid in Table

¹

LIPID METABOLISM com positions

(Table 1)

of the

OF THE

f ats

LUNG

and ^oils administrated

239 are

Fatty Acid

Table Compositton of

1

various Fats and ^Oils

Fatty Acid

8:O

10 : O 12 : O 14 : O 16 : O 16 : 1 18 : O 18 : l 18 : 2 18 : 3 20 : l 22 : l

Safflower Oil

10

4

l 6

66 3 .2

.4 .l .2

Olive Oil

24 o 5 64 4 o .5 .9 .3 .5 .7 .6

Beef Tallow Coconut Oil

2 31

24 37

.7 .5 .3 .7 .7 .4

4.8 6.6

45 , 2 18 . 8

ll.5 3.8 8.l l.l

Butter

2 2 9 25 2 14 28 2 .5 .8 .9

.8 .8 .3

Sesame Oil

8

3 32 33 4 13 .g

.6

.5 .5

.4

In group I the lung, Iiver, heart, kidney and spleen were quickly removed and weighed for lipid analysis, and in the other five groups the lung and the liver were quickly removed and weighed for lipid

analysis.

(2) Experiment II

After fasting for 12 hours, 5 rats in each group were orally admi‑

nistrated for triglycerides (tripalmitin, tristearin, triolein and trilinole‑

in) by a stomach tube. Six hours after the administration the animals were exsanguinated under Nembutal anesthesia, and then the lung and the liver were quickly removed and weighed for lipid analysis.

(3) Lipid extraction and analysis.

Lipids were extracted from these organs by the method of FOLCH and LEES.22) Total lipids were measured by the gravimetric method and dissolved in 10 ml of chloroform. The solution was used for the next measurement. Triglycerides were measured by the method of VAN‑HANDEL and ZILVERsMrr,23) phospholipids by ALLEN'S method24) and total cholesterol by the method of ZAK25) and HENLY.26) Lipoprotein lipase (LPL) activity was measured by the method previously reported by YAMADA. 16)

(4) Separation of lipid

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G. MAMEYA

Silicic acid chromatography was employed to separate the extracted lipid into simple lipid and phospholipid by MIYAHARA'S modification27) of HIRSCH and̲ AHREN'S method. Silicic acid (100 mesh) was obtained from the Mallinckrodt Chemical Works. A column measuring 1.5 cm in diameter and 30 cm in length with a glass filter was prepared.

Silicic acid was activated at 120'C for 12 hours. The column was prepared by filling the column with petroleum ether and adding 6 g of the activated silicic acid. Then, before the separation, the column was washed with following solutions : 20 ml of ethyl ether, 30 ml of acetone‑ether (1 : 1) and 50 ml of ethyl ether‑petroleum ether (1 : 1).

The lipids to be separated were added to the top of the column in a small volume of ethyl ether. Simple lipid was eluted with 150 ml of petroleum ether‑ethyl ether (1 : 1), and phospholipid with 150 ml of methanol. Whether lipids were separated or not was confirmed by thin‑layer chromatography.

(5) Gas‑chromatographic analysis.

When gas‑liquid chromatography (GLO is used, tbe fatty acids are usually converted to their respective methylesters prior to their analy‑

sis. A number of authors28)29)30) have described the procedures for preparing methylesters of fatty acids prior to GLC analysis. METACAL‑

FE et al.31) and VORBECK et al.32) stated that there was no difference in the GLC pattern by each method of methylesterification. In this experiment, STOFFEL'S method28) was used for reason of simplicity and

re liability .

Analytical condition of gas‑1iquid chromatography

In the analysis by GLC, its suitableness is dependent upon the operational condition of GLC, and the choice of column used. The analysis of the separated lipid was performed in condition as shown in Table 2. (Table 2)

Table 2

Analytical Condition of Gass Liquid Chromatograhy Apparatus SHIMADZU GC‑lB

Column Diethylenglycol Succinate 15 on Shimaleite Support mesh 60‑8,0

I. D. 4mm Length 3m Column Temp. 200‑C Sample Temp. 280' C Detect. Temp. 220 C

Carrier Gas He Flow Rate 30 ml/min. Press 3.0 kg/cm2

Detector Hydrogen Flame lonizaton Detector (Typ3 HFD‑1)

H2 Flow 70ml/min. Air Flow 700 ml/min

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LIPID METABOLISM OF THF LUNG Qualitative and quantitative analysis

For the identification of each fatty acid, pure reagents (lauric acid (12 : O), myristic acid (14 : O), palmitic acid (16 : O), palmitoleic acid (16 : 1), stearic acid (18 : O), oleic acid (18.1), Iinoleic acid (18 : 2), linolenic acid (18 : 3), arachidic acid (20 : O), and arachidonic acid (20 : 4) ) were methylesterified respectively, and the fatty acid reten‑

tion time was obtained for each apparatus. Each retention time is shown in Table 3. (Table 3)

To inject fatty acid methylesters into GLC, JlNTAN'S microsyringe (10 pl) was used.

Table 3

Retentron Trme of the Fatty Acid Methylesters

Fatty Lauric Myristic Palmitic

Palmitoleic Stearic Oleic Linoteic Linotenic

Arachidic

Gadoleic

Arachidonic Behenic

Erucic Lignoceric

Nervonic

Measurement Percentage this it is necessary each component.

area calculations.

height by width at one‑half base width, retention time, (d) measurement of measurement of area tion are well chosen essentially the same the basis of ease and was used.

Acid

12 14

l 6

16 18

l 8 l 8

18 20 20 20 22 22 24 24

O O O l

O

l 2 3 O

1

4 O

O

Retention

Time

2!

4!

6!

71 11 / 13 !

16/

21 ! 20 ' 22 ! 37 / 35 / 40 ! 63 ! 70 !

30n 03n

4 8 n

57n 42n

2 u

39u 58n

l 8n l 2 n 5 1 n 4 8 n

09u

3 O n

15u

O . 3676 O . 5956 l . OOGO 1 . 1691 l . 7206 1 . 9779 2 . 4485 3 . 2309 2 . 9853 3 . 2647 5 . 6662 5 . ･ 647 5 . 9044 9 . 3382 l O . 3309

composition calculations are carried out commonly; for to obtain an area measurement associated with Many different procedures have been proposed for Methods in use include (a) multiplication of peak half‑height, (b) multiplication of peak height by (c) multiplication of peak height by adjusted measurement of peak area by planimetry, (e) peak area by weighing the cut‑out peak, and (f) integrators. When the conditions of the separa‑

, all of these methods of measurement produce

results, and the choice of method is then made on

experience. In our laboratory the method of (e)

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G. MAMEYA

RESULTS

Experiment I

1. Lipid composition in each organ after administration of various kinds of fats and oils.

(a) Lung lipid composition. (Table 4, Fig. 1)

The amount of total lipid showed a slight increase in the groups I, 11 and VI, especially in the group I. In the amount of phosphol ‑ pid, a marked increase was observed in the group I, and a slight increase in the groups II, IV and V. The triglyceride content increa‑

sed in the groups I, 11 and V, and the total cholesterol content in the groups I, V and VI. That is, the group I presented the increase of all the lipid fractions, the group 11 mainly the increase of triglyce‑

ride, and the group VI principally the increae of total cholesterol.

Table 4

Lung Lipid Composition after Administration of various Fats and Oils in Rats

Control Safflower Oil Olive Oil

Beef Tallow Coconut Oil Sesame Oil Butter

Liver Lipid and OilS in

Total Lipid Phos pholipid Triglyceride

Total Chelesterol

41.5+̲6.9 23.9̲+2.5 6.3̲+3.0 1 6.8 1.2 48.2 5.3 i 32.5̲+3.6 Il.1̲+6.3 l0.7 0.7 44.9̲+7.2 25.5 3.2 8.7̲+5.2 7.7̲+0.6 41.5̲+4.1 ' 25.3̲+0.8 5.4 1.6 7.8 0.8 43.3 4.9 1 26.3̲+2.2 4.4 2.2 8.2̲+0.g

42.7 2.5 27.0 2.3 5.6 2.3 8.8 0.9

45.5+4.4 , 24.1 2.8 6.0̲+2.4 l0.7 0.8

COmpOSitiOn after AdminiStration Of VariOuS Fats Rats

Total Lipid Phospholipid Triglyceride Tatal Cholesterol

Control 51 . 7 5 . 3 Safflower Oil 57. 4 7. l

Olive Oil 51 .0+4.6

Beef Tallow 50 . 0 3. 3 Coconut Oil 50.3+̲2,6 Sesame Oil 54.3 2,9

Butter 53 . 7 ̲+ 3 , 9

^I

mg/g of wet weight

38 , 3 2 . g

4A,3 3.5 35.9 1.3

37.8+̲1.0

34.7 1,6

36.2 +̲ I . 8

39.6 2.6

4.3: ;1.3

9.4 5.l

8.0 ̲2.4 3.3+̲0.9 5.3d::1.5 7.1̲+̲1.2

5.4+1.8

8.2 0.9

l0.4 1.2

7.0+0.9

6.7+0.7

8.3 0.4

8.6+̲0.6 l0.6+̲1.3

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1967 LIPID METABOLISM OF THE LUNG ²⁴³

50

40

30

20

10

Fig. 1. (A) Lung Lipid Total Lipid

Composition after

Administration

of various Phospholipid

Fat s

and

^Oils

(1)

( 6)

(1) (2)

Control

Coconut

(3) (2) Oil

(4) (5) (6) Safflower Oil (3)

(7) Sesame Oil

(7)

Olive Oil

(1) (4)

(2)

Butter

(3) (5)

(4)

Beef

(5) (6) Tallow

(7)

Fig.

1 ･ (B)

Lung

Lipid Composition after Aministration of

various Fats and

^Oils

15

10

5

Triglyceride

15

10

5

Total Cholestero]

(1) (6)

(1) (2)

Control

Coconut

(3)

(2) Oil

(4) (5) (6) Safflower Oil (3)

(7) Sesame Oil

(7)

Olive Oil

(1) (2)

(4) Butter

(3)

(5)

(4)

Beef

(5)

Tallow

(6) (7)

(b) Liver lipid composition. (Table 4, Fig. 2)

The amounts of total lipid and phospholipid were recognized to

increase in the groups I and II. The amount of triglyceride increased

in the groups I, 11 and V, and that of total cholesterol in the groups

I and II. Thus, the liver lipid composition was observed to change in

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244 G. MAMEYA ^Vol. 11 approximately the same

change was remarkable way

in the

as the group

lung

I.

li pid

com position , and ^the

50

40

30

20

10

Fig. 2. (A)

Liver Lipid

Composition

^af ter

(1) (2) (3) (1) Control (2) (6) Coconut Oil

(4) (5) (6) Safflower Oil (3)

(7) Sesame Oil

(7)

Olive

Administration

50

40

30

20

10

(1) (2) Oil (4) Butter

of varrous Fats

P ho s pho]i pid

(3) (4)

(5) Beef

and

(5) (6) Tallow

Oils

(7)

20

15

10

5

Fig .

2. (B) Liver Lipid

Triglyceride

Com position after

Administration

Total

15

10

5

of various Cholesterol

Fats and

Oils

(1) (2) (3) (1) Ccntrol (2) (6) Coconut Oil

(4) (5) (6)

Safflower Oil

(7) Sesame Oil

(7)

(3) Olive

(1) (2) Oil (4) B tter

(3) (4)

(5) Beef

(5) (6) Tallow

(7)

(9)

1967 1.IPm METABOLISM OF THE

(c) Lipid composition of the heart, administration of safflower oil. (Table 5)

Table 5 Lipid Composition of Heart, Kidney and tration of Safflower Oil in Rat

LUNG kidney

S pleen

and

af ter

s pleen

Adminis‑

,245

af ter

Total Lipid

Phos pholi pid Triglyceride

Heart

Control

Safflower Oil

31.2 2.7 , 24.7̲+2.3 :

32 . 8 3 . I : 24. I +̲ I . 6 l

^2.

2.

0 0.

l+0.

5 7

Total Cholesterol

4.

3.

3+0.

5+̲o.

9 2

Kidney

Control Safflower Oil

42 . 3 + 3. g

42.0 3.2

29 . 9 + 2 .6

28.6+1.4

3.5+0.9

3.8+̲1.8

8.6+̲2 7.3: l .8 .o

Spleen

Control ' 28.0 7.7 ! 5.5̲+0.8

^15.5+̲2.0

^{0.8 0.2}

Safflower Ou 25 . 2 5 .2 5. 2 0 . 5

^14.8+̲1.4

^{l.2 0.1 ,}

mg/g of wet weight

The lipid composition in the heart, kidney and spleen was not recognized to suffer any marked change in the group I where the most remarkable change was found in the lung and the liver.

(d) Lipid compositions of the lung and the liver 3, 6 and 9 hours after administration of safflower oil. (Fig. 3)

Flg' 3. Lipid Composition of Liver and Lung after Administration ot Safflower Oil

Live* L"ng

c l T't*1 LiPid 50

40

50

!o

b'f'* ' h'' 6 h'*' 9 h'‑' 5 h.. 6 h'‑' 9 h'‑'

^b. t'*'

(10)

G. MAMEYA

Three hours after the administration, every lipid fraction was observed to increase in the lung, but only triglyceride was found to increase in the liver. Six hours after, all the lipid fractions were observed to increase in both lung and liver, but they decreased 9 hours after.

(e) Lipoprotein lipase act,ivity (LPL activity) in the sera and the lung 3, 6 and 9 hours after administration of safflower oil. (Fig.4)

Flg 4' Lipoprotein LiPase Activity ot Serum and Lung arter Administration ot satnower On in Rat

vE'I

125t59 242i76 559t94 159i45 427i56 558t95 452t59 ,67 :59

The LPL activity of the sera increased sequentially 3 and 6 hours after, and resumed the original value 9 hours after. The LPL activity of the lung was highest 3 hours after and decereased gradually after‑

ward to become below the original value 9 hours after. Judging from this fact, the lung is considered to produce LPL activity in an early time after the administration of fat, and to incorporate fatty acid yielded by the hydrolysis of the fat administrated to cope with alimen‑

tary hyperlipemia.

II. Fatty acid composition of each lipid fraction in each organ after administration of various kinds of fats and oils.

(a) Fatty acid composition of each lipid fraction in the lung.

(Table 6) ,‑

As for the simple lipid fraction, the group I showed a remarkable

increase in the amount of linoleic acid which occupied about 70% of

safflower oil, and the group 11 in that of oleic acid which occupied

(11)

1967 LIPID METABOLISM OF THE LUNG ²⁴⁷ about 65 of olive

showed an increase found in the other

oil. As for

of linoleic groups .

the acid,

phospholipid fraction, the

but no marked change

group I could be

(b) Fatty acid composition of each lipid fraction in the liver.

(Table 7)

As for the simple lipid fraction, the group I and group 11 showed some increase of linoleic acid and oleic acid, respectively, and the group IV a slight increase of lauric and myristic acids. Thus the fatty acid compositions of the fats and oils administrated were reflected.

As for the phospholipid fraction, the group I showd the increase of linoleic and arachidonic acids, and the group 11 a slight increase of oleic acid.

(c) and liver 3 8, 9)

Fatty

, 6 and

acid composition of each lipid 9 hours after administration of

f raction saf f lower

in the lung oil. (Table

Fatty Acid Composition Fats and Oils

simple Lipid Fraction

Table of Lung

6

af ter

Admmrstration of various

Fatty Acid#

Control

Saf f lower‑Oil

Olive Oil

Beef ‑Tallow

Coconut Oil Sesame Oil Butter

l 2 : O

0,1 0.l 0.l 0,l 0,2 0,l 0.2

14:O l.9+̲0.6 2.0+̲0.6 }1.4+̲0.3

:1.1+0.6

:3 . I +̲O. 7

i3.2+̲0.9

1.6 0.5

16 : O

I 16:l

l 8 : O

30.2+2.

26 . 8 +̲ 4 . 29 . 5 + 3 .

32.7+̲3.

32. 9 + 3 .

32.4+̲2.

29. I + 3.

5 5 7 4

8

7.0+̲1.317.8+̲0.6

5.3 1.36.3 1.l 5.9+̲1.75.9 0.5

6.9H̲‑0.9'7.8+̲0.9

6.5+̲0.86.9 0.6

8.5+̲1.18.0+̲0.7

18:I

24 . 7 + 2 . 4 22. 0 I . 6 32 . 6 + 7 . 2

26.7+̲3 1

23.6 2.6

20 . 3 d:;2 . 2

6'3+̲3'1 6'7+̲0'71 27'1 2'9' 18:2

20.2+2.1

30 6+̲7.8 17.9+̲2.7

19.9+2.0

20. 2 + 2. l

20.7+̲1.9

21.9+̲2.3

18 : 3 20 : 4

Phospholipid

Fraction

l

0.7+0

l.6+̲O.

0.8+̲O l.2+̲O.

0.5 0

l.5+̲O 0.9+̲O.

.55.

44

.64.

42.

.35.

.77.

44.

4+̲1.4

.0 0.4 0 2.4

9+̲1.8 4+̲1.2 l+̲2.6 9+̲1.3

Fatty Acid l

Control Safflower Oil Olive Oil

Beef Tallow Coconut Oil Sesame Oil Butter

# Chin length

14:O 16:O ^16 : l

2.7 0.8

2.5+0.4

2.0+̲0.3

3.4 1*O

,4 .6 I . 3i

3.0+̲0.7

13 . 2 O . 9:

No. of

18:O

' '1 ' '

31.3+̲7.413.9 0.5 19.6 2.s 39.5 3.8i2.5 0.6

35.7 5.52.6+̲0.4 39.4+̲3.24.2 1.3 38.9 3.9[3.7 1.l

47 . 3 +̲ 4 . 812 . I 0 . 91

20. I 2 . l

19.6 2.4

18.4+̲1.6 17. 8 1 .9 16 .9 2 . O

18 : l 18:2 15.6+̲1.0

15 . O +̲ O . g:

17.3 1.2

17 . o +̲ I . 3, 12 .7 +̲ I . 5.

17.4 1.0

18:3

31.8+̲6.1:2.9 0.81 21.0+̲1.81 17.5+̲1 .2

double bonds

7.9+̲0.7 l0.3+̲0.9 8.1+̲1.0 9.3+̲1.0 7.1+̲1.2

8 . 3 ̲+ O.

1 9.8 0.8,

20 : 4

l0.9:h2.0 l0.8: l.7 ll.1+̲1.0

9.7 1.8 8.5 1.6

12.8:1:2.5

13.0 2.3

Values expressed as of total fatty acid methylesters

(12)

248 G．MAMEYA

^70」．11

After3hours，in the phospholipid fraction of the lung，the increa−

se of linoleic acid was observed，but no increase of linoleic acid could be noticed in the simple lipid fraction．In the simple lipid fraction of the liver， 1inoleic acid increased， and in the phospholipid fraction，

arachidonic acid increased． After6hours，both in the simple lipid fraction and in the phospholipid fraction of the lung， 1inoleic acid increased． In the liver，the simple lipid fraction showed an increase of linoleic acid，and the phospholipid fraction showed an increase of linoleic and arachidonic acids．After9hours，the fatty acid composi−

tion of the simple lipid fraction in the Iung resumed the value before the administration，but in the phosPholipid fraction，an increase of linoleic acid was the same as that after6hours，and an increase of arachidonic acid was noticed． In the simple lipid fraction of the liver，

the amount of linoleic acid gave a little lower value than after6hours，

but in the phospholipid fraction，it remained same as after6hours．

That is，in both lung and liver，linoleic acid was presumed to be in−

corporated into their phospholipid fractions as a component of them either in its own form or in its converted form to arachidonic acid．

Table 7

Fatty Acid Composition of Liver after Administration of various Fats and Oils

Simple Lipid Fraction

Fatty Acid＃

Control Safflower Oil Olive Oil Beef Tallow Coconut Oil Sesame Oil

Butter

12：0

0．1 0．1 0．1 0．1

14：0

2●3

1暢士1：IF

。．311．。土。．51 E

イ 1：1士1：ll

O．4土0．2 0．3±0．21 1

16：0 16：1

29．1±4．5 29．3土3．8 28．5土1．8 30．4土2．9

2．2土1，0 1．6土1，11

1．6土04

1．1土1．Ol

18：0

12．3土1，2 10．8土1。5 12．6土1．9 13．5±1．4 30・5土3・O L9土O・812・9土L 24・5土3・2rL9土0・21L4土0・8 26。5土3、41。8土0．7 16．7土2．1

18：1 16．2±1．2 1 13．0土2．41 25。2±3。4 16．8±2．1 14、7土1．8 17．5土1．7 15．6土2，01

18：2

23．1土2，5 33．5土4．6 18。8土2．7 20．9土2．4 21．8土2．2 25．4土2．1 17。4土2．6

18：3 1，1土1．1 1．1土1，0 0．6土0．5 0．6土0．4 0．6土0．5 2．2土1，2 0．5土Q．3

20：4

13．9土2．2 9．9±2．5 12．2土1，8 15．5土2．1 12．2±2．4 13．5土2．0 17．9土2。9

Phospholipid Fraction Fatty Acid

Control Safflower Oil Oilve Oil Beef Tallow Coconut Oil Sesame Oil

Butter

14：0 0．2土0．1 0，1 0．1 0．l O．3土0．1 0．2 0．1

16：0 19．1±1，3 16．2土2．3 20．1土1．0 20．9土1．2 21．3±2．0 18．5±1．8 21．4土1．4

16：1 0．6±0．2 0．5土0．2 0．4±0．1 0．4±0．2 0．4土0．1 0．8±0．3 0．5土0．2

18：0

30．3土1．2 29．6土1。0 30．8土1。9

18：1 6．8土1．1 5．1±1．2 7．8±1．2

18：2

30．5土1．36．2土1．4

旨

30．1土1．76．3土1．7 28．7土2．17．2土1．3 30．3土2．06．2土1．6

18．1土2．1 20．5±2．O l8．0土0．7 17．9土1．8 18．9土1．5 19．3土2．1 16．7土1．7

18：3

0．6

20：4

＃ Chain Iength No．of double bonds

23．6土2．2 27．5±2．4 23．8土1．8 22．4土2．1 22．2土2．0 23．8土2．3 24．2土2，1

Values expressed as％of total fatty acid methylesters

(13)

1967 LIPID METABOLISM OF THE LUNG ²⁴⁹

Tadle 8

Fatty Acid Composition of Lung at time intervals of3，

hours after Administration of Safflower Oil in Rat

6and9

Fatty Acid＃

14 0 16 0 16 1 18 0 18 1 18 2 18 3 20 4

Contro1 ＃＃

1．9土0．6 30．9±2．5

7．0土1．3 7．8土O．6 24。7土2．4 20．2土2．1 0．7±0．5 5．4土1．4

after Administration

3 hours ＃＃＃

1．9土O。4 29．0土2．5

7。3±0．6 7．9土0．6 23，8土3．4 21．5土2．O O．9±0．4 6．0土1．8

6hours

2．0±O．6 26．8土4．5

5．3土1．3 6．3土1．1 22．0±1．6 30．6±7．8 1．6土0．4 4．0土0．4

9hours

2．7土O．5 30．8土3。7

8．0土0．5 7．9土O．9 24．9±5．1 18．3土2．0 1．1土0．3 4．8土1．6

Phospholipid Fraction

Fatty Acid＃

14 16 16 18 18 18 20 ＃

＃＃

＃＃＃

0 0 1 0 1 2 4

Chain length

Contro1＃＃

2．7土0．8 39、5±3．8 2．5土0．6 20．1±2．l l5．6土1．0 7．9土0。7 10．9土2．O No，

after Administration

3 hours＃＃＃

2．5土0．7 33．5±2。8

3．5土O．4 20．6±1．O l6．9土1．8 9．1土0．8 10．8±1．7

6hours

2．5±0．4 35．7土5．5

2．6±0．4 19．6±2．4 15．Q土0．9 10．3土0．9 10．8土1．7

9hours

of double bonds Mean of lO caces

Mean of5caces

3．3土O．4 27．3±2．7

3。6±0．5 23．6土1．4 18．4土1．2 10．1土1．6 11．7土1．6

Table 9

Fatty Acid Composition of Liver at time intervals of3，

hours after Administration of Safflower Oil in Rat

6and9

Fatty Acid＃

14 0 16 0 16 1 18 0 18 1 18 2 18 3 20 4

Contro1＃＃

0．5土O．2 29．1土4．5

2．2土1，0 12．3土1．2 16．2土1．2 23．1±2・5 1．1土1．1 13．9±2．2

after Administration

3 hOurs＃＃＃

0．3土0．1 26．0土2．8

3．O土1．1 9．7土1．3 18．1±1．6 27．3土3．2 1．7土0．9 12．8土2．4

6hours

0．5土0．2 29．3土3．8

1．6土1．1 10．8±1．5 13．0土2．4 33．5土4．6 1．1土1．0 9，9±2．5

9hours

0．5土0．2 25．O±3．2

2．6±1．O l1．2±1．1 15．1±1．4 29．9土3．5 1．9土1．2 12，1土2．0

(14)

250 G．MAMEYA

^70Z．11

Fatty Acid Control 14

16 16 18 18 18 20 ＃

＃＃

＃輔

0 0．2土0．1 0 19．1土1，3 1 0．6土0．2 0 30．3±1．2 1 6．8．士1．1

218．1．±12．1

4 23．6ニヒ2．2 Chain length ： No．

Mean ofユO cases

Mean of5cases

after Administration 3hOurs

0．3土0．1 17．4±2．3

0．8土0．2 27．5土0．6

7．3土0．4 19．3土1．4 26．2±2．1

6hours

0．1 16。2土2．3

0．5土0．2 29．6±1．0

5．1土1．2 20．5土2．0 27．5土2．4

9hours

of double bonds

O．2土0。1 15．5土1．O

O．6土0．1 28．8土1．1

7．2±O．8 20．8±1．7 25．3土2．4

Table 10

Fatty Acid Composition of Heart，Kidney and Spleen after Adminiatration of Safflower Oil

Fatty Acid＃

Heart

Kidney

Control Safflower Oi1

14：0 16：0

1．3土0．3120。Q±1。1 1．3土0。2117．1ゴこ1．6

16：l l8：0

2．6±Q．8 22．8±O。6 2．0．一⊥；0．9 206置二2．4

1．9土O．6 1．5土0．4

25・1土2・1 3・4土0・4 23・4±2・q3・5±G・4

11．0土0．9 11．1±0．9

18：1

14．5±1．4 14．3土1．1

18：2 18：3

18．3±3．2 Q．1 23。6土3．1 0．7±0．4 1 1

20．4土1．8119．3土2．Ol 2・．7土・．4121．9±・．5…

！

20：4

17．4±1．3 16．4土2．8

Spleen

C。ntr。1 11．1土0．329．6土2．53．5土O．2ロ2．4土1．6118．5土2．3

Saff1・werOill2・4±0・830・3土3・4r4・7土0・7、IL4土・・Oll9・9±2・4

1．2土0．3115．0土4．9 L2土0・・ll3・4±3・2

14．0±2．3

18・7土L6LO±O・5，

13．4±5．4 8．0土3．4

Fatty Acid＃

Heart

Kidney

Control Safflower Oil Spleen Control Safflower Oil 辞

14：0

1．9土1．5 0．8土0．4

1．1土0．1 1．2土0．1

16：0 16：l l8：0

10．7±2。81L2±0．4 11L．1土1．51．1土0．2

24．8±1．6 27．1土1．2

14．0±2．0 11．6土1．2

L3土0・2124・4土2・6 L・土・・3127・5土3・4 No．

1。7土0．2 1．8±0．2

1．9土0。41 1．8土0．2「

of double bonds

21．8土1．8 22．0±O．7

29．9土3．2 29．5土2．7

18：1

7．7土0．7 7．6土O．4

18：2 18：3

33．6土3．9 31．0±4．8

10．9土0．7 11．2±0．4

18．2土1．7 18．6土1．4 0．2

13．1土1．3 13・8±L71

9．2土1，41 9．6土1。0

20：4

16．6土1．8 18．O土1．4

29．3土2．0 30．1土0．6

Chain length 3

17。2土4．7 11．2±2．8

(15)

1967 LIPID METABOLISM OF THE LUNG ²⁵¹

（d） Fatty acid composition of each lipid fraction in the heart，

kidney and spleen after administration of safflower oi1．（Table10）

In the simple lipid fraction，a slight increase of linoleic acid was recognized in each organ，but in the phospholipid fraction，no marked change could be observed．

Experiment II

As it was presumed that the change of the lipid composition was different between the lung and the liver according to the difference of the fatty acid composition of the fats or oils administrated，Experiment II was performed in order to assure this fact．

1．Lipid composition and fatty acid composition of each lipid frac−

tion in the lung．（Table11，12，Fig．5）

The amount of total lipid incl・eased slightly in the tripalmitin，

triolein and trilinolein groups． The amount of phospholipid increased in every group，especially in the trilinolein group． The amount of triglyceride was observed to increase in the triolein and trilinolein groups，and the amount of total cholesterol in the tripalmitin and trilinolein groups． In the fatty acid composition of the simple lipid fraction，the constituent fatty acid of the triglyceride administrated was increased． In the phospholipid fraction， oleic acid increased in the

Table ll

Lipid Composition of Lung and Liver after Administration of Triglyceride

Lung Lipid Composition

Control

Tripalmitin

Tristearin Triolein Trilinolein

Total Lipid

41．5土6．9 46．7土4．5 43．1±4。5 46，8土5．1 49．O±5．2

Phospholipid

23．9土2．5 27．9土2．4 28．1±2．2 26．9土2．2 33．5土3．8

Triglyceride 6．3土3．0 6．4±3．1 6．5土3．3 10．0±4．9 10．8土5．2

Total Cholesterol 6．8土0．9 10．1±1．1

8。4土0．9 8。1土0．7 10．4土1．2

Liver Lipid Composition

Control

Tripalmitin

Total Lipid

51．7土5．3 51．5土5．1 49．5土4．3 56．O土5．7 55．5±6．4

Phospholipid

38．3±2．9 38．0土3．2 36．7±3．】

40．8土3。5 42．6土4．1

Triglyceride 4．3±1．3 3．8±1。6 3．5±1．8 5．0土2．0 8．6土4．3

Total Cholestero1 8．2土0．9 8．Q土O．8 7．5土O．6 8．5土O．5 9．3土1．1 mg／g of wet weight

(16)

252 G．MAMEYA

^70Z，11

triolein group，and linoleic and arachidonic trilin61ein group．

acids also increased in the

Table 12

Fatty Acid Composition of lmg after Administration of Triglyceride（Tripalmitin，Tristearin，Triolein，Trilinolein）

Fatty Acid＃

Control Tripalmitin

Tristearin Triolein

Trilinolein

14：0 16：0 1L9土・。613・．9圭2．51

『2。3土・。3129，6土3。4r L2土0・5125・9±2・61 1．9土0。4r27．6±1．4 2．2土0．612フ．8±2．7

16：1 、 18：0 18：1 1

「一一丁

7・0±L3、7・8土0・6124・7±2・41 6・4±0・817・7土LO133・5±2・gl 6・・土L・h・・8±L6126・1土2・71 7。6土0。716．9土0。8135．3土3．2

！

5・6土L21

18：218：31

』

＿¶．一一＿一 T l．

20．2土2．I O．7±0．5 14．5土1．0 − 1

15．2土1．11− 1

13。3土0．6『0．4 6・6土L112LO土1・7：29・0±4・31

20：4

3．4±1．4 2．6土1．6 10．9±3，2

1．6±0．5 4．0土0．4

Fatty Acid辞

Control

Tripalmitin

＃

14：0 2．5±0．8 2．0±0．3 2．6土0．3 2．9土0．5 2．1±0．7

16：0

39・0±3・81 38．7±4，2 37．9±1．51 32。2±L31 34．3土3。11

16：1 18＝0 18：1 18：2

2．3土0．6120．4±2．1 15．6土1．0−

6，2土0・5r18。3土0．gl・4．0土0、9！

6・4±0・4！17・7土L213・1±0・6 6．7±0．6113．3土0。6 16．9土0．81 3・5土・・612Ll±L・F15・5土L5

7。9土0．7 8．4±0．8 10．4土1．1

9．3土0．5 10．9土0．9

18：3 20：4

Chain length

No．of double bonds

8．7±1．3 9．0土1．1 8，2土2．3 8．7±1．3 11．0土1．8

Fig．5． Lung Lipid Composition after Administration of Triglyceride

50

40

30

20

10

Tota1 Lipid Phospholipid

0

1

（1〉（2）（3）（4）

（1） Contro1

（5）（1）（2）（3）

（2）Tripalmitin

15

10

5

（4）（5）（1）

（3）Tristearin

Triglyceride

（2）（3）（4）（5）

（4）Triolein （5）

Total Cholesterol

（1）（2）（3）（4）（5）

Trilinolein

(17)

1967 LIPID METABOLISM OF THE LUNG

2・Lipid composition and fatty acid composition of each fraction in the liver．（Table11，13，Fig．6）

Table 13

Fatty Acid composition of Liver after Administration of Triglyceride

253 Lipid

Fatty Acid＃ 14：0 16：0

C。ntr。1 16．5王6．2i29』f蜘

Tripalmitin O，4土0．236．9土4．3

1 T「istea「in IO・5土0・233・5土3・7r Triolein O．9土O．231．7±2．9

l

Trilinolein O．2土0．129．0±3．2

16：1

2．2±1。0 2．9土1．1 2。6土0．8 4．2土0．4 1．5土O．6

18：0 18：1

12、3±1．2 7．0土1．4 8．9土1．0 5．7土0．9 11．0土1．1

16．2±1．2 24．0土2．1 22．7土1．8 31。5土4．7 13．0土1．4

18：2

23．1土2．5 20．9土2．3 22．2土2．6 16．1土2．5 33．3土4．1

18＝3 1．1土1．l Q．7

20＝4

13．9土2．2 3．8土2．5 8．6土2．8 4．2土2．7 10．3土3．3

Fatty Acid＃

14：0

C。ntr。l I Tripalmitin

＃Chain length

O．2土0．1 0．1 0．1 0．1 0．1 No．

16：0 16：1 18：0

19．1土1．3 0。6±0．2130．3±1．2

19．6土1．4 1．2土0．5124．2±2．3 21．9±1．gl ．2土0．423．8土2．1 1

18。7土L711．2土0。6、25。9土L5 16・0±2・00・4土0・2

29・8±L7

0f double bonds

18：1 18：2 6．8土1．1 18。1土2．1 9．7土1．3 20．2土2．1 9．6土1．8 17．9土2．0 9．8土1．1 17．9土1．8

52土L4120・8土2・4

18：3 20：4

50

40

30

20

10

23．6土2．2 24．3土2．1 24．7±2．3 24．O土2．5 25．3土2．8

Fig．6． Liver Lipid Composition after Administration of Triglyceride

Total Lipid Phospholipid Triglyceride Total Cholesteror

15

10

（1）（2）（3）（4）（5〉（1H2）（3）（4）（5）（1H2）（3）（4）

（1）Contro1 （2）Tripalmitin （3）Tristear量n （4）Triolein

（5）（1）（2）（3）（4）（5）

（5）Trilinolein

(18)

G. MAMEYA

The amounts of total lipid and phospholipid increased remarkably in the triolein and trilinolein groups and the amount of triglyceride in the trilinolein group. The total cholesterol content increased slightly in the trilinolein group. As for the fatty acid composition of the sim‑

ple lipid fraction, the tripalmitin group showed the increase of palmitic acid, the tristearin group that of stearic acid, and the trilinolein group that of linoleic acid. As for the phospholipid fraction, the trio‑

lein group presented an increase of oleic acid, and the trilinolein group that of linoleic and arachidonic acids.

In the Experiment II, Iike the Experiment I, the lipid composition and the fatty acid composition in each lipid fraction gave an approxi‑

mately similar change in the lung and in the liver, and the change was most remarkable in the tTilinolein group. It is noteworthy that the lung and the liver presented a similar behavior to the exogenous

fat .

DISCUSSION

In this study, it is proved that after the administration of various kinds of fats and oils the lung shows some change in its lipid compo‑

sition and in the fatty acid composition of each lipid fraction and reacts to the exogenous fat in approximately the same wav. as the liver, but in a little earlier time than the liver. However, the change in the lipid composition of the lung was different according to the difference of the fats or oils administrated‑total lipid was recognized to increase in the safflower‑oil and olive‑oil groups, phospholipid in the safflower‑

oil, sesame‑oil and oilve‑oil groups, triglyceride in the safflower‑oil and olive‑oil groups, and total cholesterol in the safflower‑oil and butter groups. The increase of the total lipid content and phospholipid con‑

tent was not so remarkable as SCHRADE12) has reported, but a marked increase was noted in the group administered safflower oil.

In the Experiment II, every group showed an increase of phospho‑

lipid in the lung, which was most remarkable in the trilinolein group.

In the liver, the increase of phospholipid was observed only in the

trilinolein group.

KATOH46) in our department, from the fact that phosphatidic acid was increased after the administration of triglyceride, concluded that the phospholipid synthesis of the lung becomes active in the absorption of fat. Moreover, the lung is believed to participate in the synthesis and decomposition of cholesterol, and it has been reported that acetate‑

1‑C14 administrated in the rat abdominal cavity was incorporated into cholesterol in the lung.

In this study, the increased cholesterol content of the lung was

(19)

LIPID METABOLISM OF THE LUNG

recognized in the, safflbwer‑oil, butter, tripalmitin; and trilinolein grou‑

ps. HAVEL et al.34) obserVed in the tracer experiment that 1,/3 of the exogenous fat, which was present as chylomicron in blood, was taken up into the liver by means of pinocytosis, and 2/3 of that into extra‑

hepatic cells by means of LPL. . It is generally recognized that the lung tissue has 'LPL ac tivity,14) 15) and YAMADA16) in ()ur department has demonstrated t'nat the lung has LPL activity. as high as in the adipose' tissue, and postulated that the lung is the main organ which produces LPL.

In this experiment, enhanced LPL activity was recognized in the plasma and the lung after the administration of safflower oil, and' rise of I.PL activity took place in the lung in an earlier time than in the plasma. And according to this change, each lipid content in the･ Iung' increased sequentially after 3 and 6 hours and decreased a;ft, rward.

From this fact, it is considered that the lung copes with aliinentary' hyperlipemia by incorporating the fat administrated after its hydrol.ysis, and later releases gradually the uptaken fat. Moreover it i suggested' that a part of plasma LPL may be from the lung.

Since free fatty acids are produced by simple perfusion of'the lung with emulsified triglycerides, HElNEMANN33) has postulated that the me‑ ' chanism‑ responsible for the lipolysis is located either within or close' to the pulmonary vessels. Furthermore, he has recognized that the' lipo]ytic activity of the lung tissue, and postulated that the lung or the' pulmonary vasculature partakes in the hydrolysis of triglycerides' ente‑

ring the blood stream v.ia the thoracic duct and thus contributes to the' supply of free fatty acids for utilzation by various tissues. The' fat,ty.' acids which are the principal constituent of lipid are divided into two groups: one group which serves as energy source and the other w･hic'hl.

serves as stuctural 60mponent of the tissue. The former includes ･ maL' inly lauric, myristic, palm'itic, palmitoleic, stearic ahd oleic a'cids, and;

the latter, Iinoleic, Iinolenic and arachidonic acids, commonly termed

"essential fatty acids" because it cannot be synthesized in vivo. Ho‑

wever, arachidonic acid can be synthesized by the organism from lino‑

leic acid in the presence of vitamin B6 , ATP, DPNH and TPNH.35) After the administration of trilinolein, both lung and liver showed some increase of linoleic acid in the fatty acid composition of the simple lipid fraction, and linoleic and arachidonic acids in that of the phospholipid fraction, which suggested that conversion of linoleic acid into arachidonic acid took place in the lung as well as in the liver.

In the tripalmitin, tristearin and triolein groups, each lipid content

did not increase so much as in the trilinolein group, which can be

supposed to be because palmitic, stearic and oleic acids are utilized

principally as energy, and linoleic acid is necessary for composition of

the cell structure.

(20)

G. MAMEYA

Furthermore , the ligation of the thoracic duct brought about a decrease of linoleic and arachidonic acids in the lung lipid composition, and after the administration of trilinolein an increase of linoleic and arachidonic acids in the ligated group was small compared with the unligated group. From this fact the lung is supposed to behave acti‑

vely to the chylomicron entering the blood stream via the thoracic duct and incorporate its lipid. The alveolar epithelial cells are thought to have the constituents one usually associates with high metabolic acti‑

vity,36) and are thought to secrete the so‑called surfactant, a lipid protein complex which lines the alveoli and reduces the surface tension of the mammalian lung.41) In the absence of this surfactant, the alveoli would be lined with water and the resulting high surface ten‑

sion would cause their collapse.37) It has been stated that this surfac‑

tant is a highly surface‑active lipid protein complex with lecithin as the main phosphatide.39)40)42)

KLAUS et al.41) reported that the surface active lining of the mam‑

malian lung was formed in the mitochondria of the alveolar epithelial

cells ,

The data presented by the author and by KAToH46) showing that the phospholipid synthesis of the lung increased after the administra‑

tion of fats, and the fact documented in the literature that phospholipid turmover is high in the lung38) suggest that this synthetic pathway serves a specific purpose.

Linoleic acid is functionally important as a constituent of mitochon‑

dria,44)45) and also is supposed to be necessary for the synthesis of surfactant from the report that respiratory disease syndrome characte‑

rized by bronchial exudate and lung consolidation is often observed in chicks fed with diet of very low essential fatty acids.43) This may be the reason why phospholipid especially increased in the lung after the administration of trilinolein and safflower oil.

ACKNOWLEDGEMENT

The author is grateful to prof. Si IRO OSAJIMA. YosHINORI OHMORI M.

D., and KIYOSHI KANZAKI M. D. for their continuous helpful advices and encouragements .

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