Bilirubin excretion following feeding or the infusion of glucose in ponies.

Bile flow, during feeding and fasting, was studied in three ponies in which catheters, maintained in the bile duct over 1-2 months, drained all bile continuously. During experiments bile was returned to the small intestine, via a second catheter, by means of a small pump which also measured bile flow rates. The mean +/- S.E. of the mean rate of bile flow in fed ponies with an intact enterohepatic circulation of bile salts was 1.33 +/- 0.10 ml/kg . h, n = 13; mean +/- S.E. of the mean concentration of bilirubin in bile was 10.82 +/- 0.91 mg/dl, n = 13. The effect on bile flow and bilirubin excretion in bile of a standard feed lasting 2 h was compared with that of an intraduodenal or intravascular 2 h infusion of glucose (50 g/h) before and after a short period of fasting (approximately 2 d). Prior to the fast, bile flow and bilirubin excretion in bile rose by 38.5 and 39.0% respectively following a feed. Glucose infused intravascularly or intraduodenally did not alter bilirubin excretion. Following a two day fast, bilirubin excretion in bile rose 72.7% to 136.5% following feeding and 65.2% to 120.3% when glucose was infused either intravascularly or intraduodenally. A correlation between plasma glucose and bilirubin excretion in bile was observed when the pony was fed or glucose infused intraduodenally. When glucose was infused intravascularly a correlation was only observed in a single experiment in which glucose was infused over 10 h at the lower rate of 24 g/h. It appears that an infusion of glucose can mimic the effects of a feed on bilirubin excretion in bile following a short fast, but not preceding it.