Dietary and Thyroparathyroidal Regulation of Calcium Excretion into the Bile of Rats

Abstract

The effects of fasting and thyroparathyroidectomy on bile calcium excretion in rats were investigated. The bile calcium excretion in rats fasted for 24 hr decreased slightly in comparison with that of fed rats. A single intraperitoneal administration of calcium chloride (4.0 mg Ca/100 g) to fed rats produced a remarkable elevation of bile calcium excretion, while a significant increase was not observed in fasted rats. On the other hand, thyroparathyroidectomy caused a significant reduction of bile calcium excretion in both fed and fasted rats. This reduction was much more pronounced in fasted rats than in fed rats. In thyroparathyroidectomized rats, a single intraperitoneal administration of calcium chloride (4.0 mg Ca/100 g) in both fed and fasted rats did not produce a significant elevation of bile calcium excretion. These results suggest that the bile calcium excretion is regulated by dietary calcium, as well as by the thyroid and parathyroid glands.