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담낭내(膽囊內) 담즙의 농액 및 산성화 기전(機轉)에 관한 연구

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 Mechanisms of concentrating and acidifying the bile in the gall bladder of the dog 
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[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.
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2. Thesis / Dissertation (학위논문) > 1. College of Medicine (의과대학) > Ph.D. (박사)
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