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

The research article is about how feeding and glucose infusion in ponies affect their bile flow and bilirubin excretion, wherein it has been observed that an infusion of glucose can mimic the effects of a feed on bilirubin excretion in bile following a short fasting, but not prior to it.

Research Methodology

• The study was conducted on three ponies. Catheters were maintained in the bile duct of these ponies for 1-2 months to continuously drain all the bile. During the experiments, the bile was returned to the small intestine through a second catheter using a small pump, which also measured bile flow rates.
• The effect on bile flow and bilirubin excretion on these ponies upon a standard feed lasting 2 hours was compared with that of a 2 hour intraduodenal or intravascular infusion of glucose (50 g/h) before and after a short period of fasting (approximately 2 days).

Findings on Bile Flow and Bilirubin Excretion

• The mean rate of bile flow in fed ponies with an intact enterohepatic circulation of bile salts was observed to be 1.33 +/- 0.10 ml/kg . h, while the mean concentration of bilirubin in bile was 10.82 +/- 0.91 mg/dl.
• Before the fast, bile flow and bilirubin excretion in bile increased by 38.5% and 39.0% respectively following a feed. Whereas, glucose infused either intravascularly or intraduodenally did not have any impact on bilirubin excretion.
• After a two-day fasting, bilirubin excretion in bile rose 72.7% to 136.5% following feeding and 65.2% to 120.3% upon glucose infusion intravascularly or intraduodenally.

Correlation between Plasma Glucose and Bilirubin Excretion

• When the pony was fed or glucose was infused intraduodenally, there was a correlation observed between plasma glucose levels and bilirubin excretion in bile.
• In a single experiment where glucose was infused through the blood vessels (intravascularly) over 10 hours at a lower rate of 24 g/h, a correlation was observed.
• Therefore, the study concludes that an infusion of glucose can mimic the effects of a feed on bilirubin excretion in bile only after a short fast, but not preceding it.