Parameters affecting bile acid and bile calcium secretion
2
Issued Date
2024
Copyright Date
1987
Resource Type
Language
eng
File Type
application/pdf
No. of Pages/File Size
xii, 161 leaves : ill.
Access Rights
open access
Rights
ผลงานนี้เป็นลิขสิทธิ์ของมหาวิทยาลัยมหิดล ขอสงวนไว้สำหรับเพื่อการศึกษาเท่านั้น ต้องอ้างอิงแหล่งที่มา ห้ามดัดแปลงเนื้อหา และห้ามนำไปใช้เพื่อการค้า
Rights Holder(s)
Mahidol University
Bibliographic Citation
Thesis (M.Sc. (Physiology))--Mahidol University, 1987
Suggested Citation
Chatsri Deachapunya Parameters affecting bile acid and bile calcium secretion. Thesis (M.Sc. (Physiology))--Mahidol University, 1987. Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/100091
Title
Parameters affecting bile acid and bile calcium secretion
Alternative Title(s)
ปัจจัยที่มีผลต่อการหลั่งน้ำดีและแคลเซียมในน้ำดี
Author(s)
Advisor(s)
Abstract
Experiments were designed to investigate (i) influence of plasma Ca concentration on bile secretion; (ii) the role of Ca regulating hormones on bile Ca secretion; (iii) association of bile acid and bile Ca secretion; and (iv) possible route (s) of bile Ca secretion. The investigations were performed in fasted 170-200 g female Wistar rats which were groups into 8 groups as follows: normocalcemic, Ca gluconate-induced hypercalcemic and thyroparathyroidectomy and EGTA-induced hypocalcemic groups; each group was devided into the normal saline (normal bile flow) and sodium taurocholate-treated groups (choleresis). It was found that changes in plasma Ca concentration had no effect either on bile flow or bile acid concentration with an exception of the hypocalcemic groups which had a lower bile acid concentration when compared with the values of normocalcemic group. In contrast, the bile Ca concentration exhibited a linear correlation with the plasma Ca concentration with a ratio of 1, suggesting a passive transport of Ca from blood into bile. To test whether bile Ca secretion is controlled by Ca regulating hormones, experiments were done in thyroparathyroidectomized (TPTX) rats which received Ca gluconate solution to maintain normocalcemia (Ca clamp). Results showed that bile Ca concentration increases after Ca gluconate infusion, indicating that bile Ca secretion does not require the presence of Ca regulating hormones but is a direct function of the plasma Ca concentration. However, since bile Ca and bile acid concentrations were slightly but significantly lower than the values of normocalcemic control, the Ca regulating hormones may have some influences over the secretion of bile acid and Ca. The mechanism, however, is unknown. Plotting of bile Ca and bile acid secretion demonstrated a positive correlation in normocalcemic and hypercalcemic groups. However, the slope representing bile Ca secreted per unit change of bile acid significantly increased in the hypercalcemic groups and showed tendency to decrease in the bile acid-treated groups, when compared to the corresponding control, suggesting that bile acid and Ca secretions were not tightly coupled. Nevertheless, when the relationship of bile Ca secretion and bile flow was plotted, at the same bile flow rate, bile Ca secretion was slightly higher in the bile acid-treated group when compared to the normal saline control, indicating that bile acid has an additional effect on bile Ca secretion independent of its effect on bile flow. To investigate possible route(s) of bile Ca secretion, an intravenously infused (45)Ca used as a marker of Ca secreted from the extracellular fluid(ECF). Assumming that appearance of (45)Ca in bile within 3 min is indicative of paracellular transport and by calculating the ratio of Ca secreted from ECF and Ca secreted from cells, it was shown for the first time that approximately 80% of bile Ca was secreted from cells while 20% was secreted directly from the ECF, presumably via the paracellular pathway. Moreover, during the stimulation of bile acid independent bile flow (BAIF) by theophylline, although both portions of bile Ca were increased, the ratio was altered, i.e., the Ca secreted from ECF was increased to 25% while the Ca secreted from cells was decreased to 75%.
Description
Physiology (Mahidol University 1987)
Degree Name
Master of Science
Degree Level
Master's degree
Degree Department
Faculty of Science
Degree Discipline
Physiology
Degree Grantor(s)
Mahidol University