Stimulative effects of cortisol and testosterone on bile calcium excretion in thyroparathyroidectomized rats

The effects of cortisol and testosterone on calcium metabolism in the hepatic bile system were investigated in thyroparathyroidectomized rats. A single subcutaneous administration of cortisol (0.1 mg/100 g) or testosterone (0.1 mg/100 g) caused a significant fall in serum calcium and a corresponding increase in liver calcium. On the other hand, the excretion of calcium into the bile after a single intraperitoneal injection of calcium chloride (4.0 mg Ca/100 g) was markedly increased by the administration of cortisol (0.1 and 1.0 mg/100 g) or testosterone (0.1 and 1.0 mg/100 g). However, the bile calcium excretion was not significantly altered by the administration of thyroxine (0.1 and 1.0 mg/100 g) or vitamin D3 (20 and 100 microgram/100 g). The present results suggest that the hypocalcemic effect of cortisol or testosterone is partly based on the stimulation of calcium excretion into the bile by the hormones.