EFFECTS OF STANNIUS CORPUSCLE EXTRACTS AND 17-BETA-ESTRADIOL ON THE CONCENTRATION OF GALLBLADDER BILE CALCIUM IN THE RAINBOW-TROUT, ONCORHYNCHUS-MYKISS
Y. Mugiya et K. Hazama, EFFECTS OF STANNIUS CORPUSCLE EXTRACTS AND 17-BETA-ESTRADIOL ON THE CONCENTRATION OF GALLBLADDER BILE CALCIUM IN THE RAINBOW-TROUT, ONCORHYNCHUS-MYKISS, Gyoruigaku Zasshi, 41(2), 1994, pp. 117-122
To examine a role of calcium excretion into gallbladder bile in calciu
m homeostasis, a single administration of Stannius corpuscle extracts
from rainbow trout or 17beta-estradiol was given the rainbow trout, On
corhynchus mykiss, and serum and bile calcium concentrations were anal
ysed by flame photometry. Calcium concentrations were approximately 3.
7 times higher in bile than serum in the control fish. Calcium-roaded
fish showed marked increases in serum and bile calcium conentrations.
The simultaneous administration of the extracts effectively reduced th
e hypercalcemia after 3 h. However, the extracts did not have any effe
cts on bile calcium concentrations at any examination times. 17beta-es
tradiol induced marked hypercalcemia with a peak 10 days after adminis
tration. In contrast, bile calcium concentrations decreased to a minim
um level on the day showing a mirror profile to changes in serum calci
um concentrations (r = -0.95). These results indicate that gallbladder
bile calcium is not involved in the hypocalcemic regulation by Stanni
us corpuscle extracts, but decreases in concentration as a result of v
itellogenin synthesis in hepatocytes.