Metabolism of N-Butyrate by the Adult Goat

Abstract

N-butyrate-l-C 1' was injected intravenously into four adult goats. Observations were made on the subsequent incorporation of C :4 into liver and muscle glycogen and into various organic acids of blood, taken either from the jugular vein or simultaneously from both the carotid artery and ruminal vein. Though several acids were labeled with C ~*, fl-hydroxybutyrate exhibited the highest specific activity. Ruminal vein blood contained over twice as much fl-hydroxybutyrate as did blood from the carotid artery. The concentration of n-butyrate in ruminal vein blood was frequently lower than that of iso-butyrate, even though the ratio of these two acids in the tureen fluid was approximately 7:1. This suggests that fl-hydroxybutyrate is a normal intermediate in the metabolism of n-butyrate absorbed from the rumen and that the rumen epithelium is a major site of this conversion. The lactate of ruminal vein blood was slightly greater in concentration but several times higher in specific activity than lactate of arterial blood. Glucose from both liver and muscle glycogen was labeled with C:' predominantly in Carbons 3 and 4, the ratio of labeling between these two carbons being approximately 1:1.