담낭내(膽囊內) 담즙의 농액 및 산성화 기전(機轉)에 관한 연구

Abstract

[한글]

[영문]

It is widely known that the bile is considerably concentrated as well as

acidified within the gall bladder. However, the underlying mechanism(s) is not

clear at present. In order to understand these processes, various solutions were

introduced into the gall bladder which was previously cannulated and the changes in

the volume and the composition were determined.

1) Permeability Characteristics of Gall Bladder:

10ml. of soltions of NaCl, urea, and sucrose isosmotic with plasma were

introduced into the gall bladder, and changes in volume were followed for a period

of 2 hrs. Distilled water was also used for comparison. The gall bladder wall was

highly permeable to urea and distilled water and less permeable to NaCl, while it

was not to sucrose.

When various sucrose solutions(0.1, 0.2, 0.3, 0.4, 0.5M/L) were introduced and

the changes in the volume were followed until non further change could be detected

at least for 1 hours, the final fluid volume within the gall bladder varied as a

function of the existing osmostic pressure gradient, indicating that the gall

bladder under some conditions resembles an osmometer, thus the transport of water

through gall bladder wall was carried out by a passive mechanism.

2) Concentrating Mechanisms:

When the various mixtures of isosmotic sucrose, NaHCO^^3 and NaCl solutions were

introduced into the gall bladder, and the change in the volume as well as in the

concentration of certain electrolytes(e.g. Na**+, Cl**- and HCO^^3 **-) were

followed until no further changes could be detected for at least 1 hour. The gall

bladder wall as able to absorb these electrolytes and there was a corresponding

reduction in the volume. The final lowest concentrations of Na**+, Cl**- and

HCO^^3**- were found to be approximately 20, 10 and 10 mEq/L, respectively. These

values are much lower than those of plasma, indicating that electrolytes are

transported against the concentration gradient. Moreover, this ability to absorb

the electrolyte was abolished in presence of 10**-2 M/L of monoiodoacetic acid, but

not in presence of 2, 4-DNP, NaF or KCN, suggesting that the energy for the

electrolyte absorption is supplied by the glycolytic process. Since the gall

bladder bile, as well as the hepatic bile, was isosmotic with plasma, it is

concluded that the primary event of concentrating the bile within the gall bladder

is the active absorption of Na**+, Cl**- and HCO^^3**- accompanied by water.

3) Acidification of Bile:

The pH of the hepatic or gall bladder bile as well as artificial solutions was

highly dependent upon the HCO^^3**- concentration in them under the same pCO^^2.

Even when a large amount of Diamox was administered, the transfer rate of HCO^^3**-

across the gall bladder wall was not altered, indicating that carbonic anhydrase is

not perhaps involved in this mechanism. According to the results mentioned above,

it may be concluded that the acidification process of the bile within the gall

bladder is probably carried out by HCO^^3**- absorption and not by the H**+

secretion.