Infusion of Sodium Bicarbonate-C 14 in Sheep. ∗

Abstract

Summary

The carbon dioxide pool system of sheep was evaluated by the constant infusion of sodium bicarbonate-C¹⁴ for a period of 4 hours. The specific activity of blood CO₂ plateaued during the final hour of infusion. Following infusion, the half-lives of blood and expired CO₂ were 32.6 and 31 minutes, respectively. Mean turnover rate, turnover time and CO₂ space were 9.58 meq/hr/kg body weight, 46.8 minutes and 41.4% of body weight, respectively. Considerable radioactivity was found in the rumen at the end of the infusion period, These observations suggest a time of at least 3 hours for complete labeling of the CO₂ pool, of which the rumen is a part, and that blood CO₂ data may be used as well as expired CO₂ data for substrate oxidation studies.