BILIRUBIN EXCRETION FOLLOWING FEEDING OR THE INFUSION OF GLUCOSE IN PONIES

¹ The Physiological Laboratory, Cambridge CB2 3EG

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.