Calcium excretion into bile in relation to starvation, calcium load and 17β-oestradiol administration in the rainbow trout, Oncorhynchus mykiss

Abstract

1. 1. Changes in calcium levels in gallbladder bile were examined in relation to starvation, calcium load and 17β-oestradiol administration in the rainbow trout, Oncorhynchus mykiss. 2. 2. Bile had a 3–4-fold bile-to-serum ratio for calcium concentrations. About 90% of total bile calcium was present as diffusible calcium. 3. 3. Seven-day starvation caused an increase in bile calcium concentrations. No effect was found in serum calcium, serum sodium and bile sodium concentrations. 4. 4. Intraperitoneal calcium load resulted in peak increases in calcium concentrations in serum and bile after 1.5 and 3hr, respectively. 5. 5. A single administration of 17β-oestradiol caused an increase in serum calcium concentrations. However, bile calcium concentrations remained unchanged. 6. 6. An inverse relationship between serum and bile calcium concentrations occurred among individuals sampled 10 days after oestradiol administration.