Splanchnic metabolism of propylene glycol infused into the jugular vein of steers under washed rumen conditions

The splanchnic metabolism and blood to rumen flux of propylene glycol (PG) infused into the jugular vein of steers, implanted with permanent indwelling catheters in major splanchnic blood vessels as well as a rumen cannula, was investigated under washed rumen conditions. Up to 95% of the infused PG was taken up in splanchnic tissues. The hepatic uptake of PG accounted for up to 70% of the PG infused though the hepatic extraction ratio was only 8%. Up to 9% of the infused PG was transferred to the buffer incubated in the washed rumen. Increased hepatic balance of L-lactate could account half of the hepatic PG uptake. In conclusion the liver is the quantitatively most important organ for PG uptake from the blood, however, up to about one third of blood PG could be transferred back to the lumen of the gastrointestinal tract. L-lactate is a quantitatively important product of PG metabolism in the ruminant liver.