(The FASEB Journal. 2008;22:1205.5)
© 2008 FASEB
(The FASEB Journal. 2008;22:1205.5.)
© 2008 FASEB
Urinary excretion of both D- and L-lactate using a calf-infusion model
Gordon Alexander Zello1,
Alisha Janzen2,
Saman Abeysekara1,
Don Hamilton2,
Jonathan M. Naylor1 and
Katharina L. Lohmann2
1 College of Pharmacy and Nutrition
2 Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
ABSTRACT
D-lactic acidosis is recognized as a complication of gastrointestinal diseases in humans and ruminants. Absorbed D-lactate can be excreted via the kidney; however, competition between D- and L-lactate in the renal mechanisms may effect its elimination. The objective of this study was to measure D- and L-lactate clearance in a calf infusion model. Five calves (age 14–31 days, weight 59 ± 8 kg) were infused with DL- and L-lactic acid (300 mmol/L, 2 mL/kg/h for 8 hours) in a randomized cross-over design. Calves were fitted with intravenous catheters for infusion and blood collection, and with suprapubic bladder catheters for urine collection. Samples for blood gas analysis, serum and urine D- and L-lactate concentration, urine volume and serum and urine creatinine were collected every 2 hours for 24 hours. D- and L-lactate clearances were calculated for each 2 hour interval and compared to creatinine clearance. With infusion of DL-lactate, average serum D-lactate concentration at steady state was 2.9 ± 1.6 mmol/L (range 1.8–5.7 mmol/L), and average urine D-lactate concentration was 4.0 ± 1.7 mmol/L. Average D-lactate clearance during steady state was 7.4 ± 3.4 mL/min. Percent excretion of infused D-lactate increased during the 8 hour infusion, with minimum and maximum excretion averaging 0.6 ± 0.1% and 10.4 ± 4.4%. L-lactate clearance could not be calculated, likely due to rapid metabolism of infused L-lactate. Therefore, L-lactate elimination is more efficient than D-lactate since it can both be metabolized and excreted from the body. (Supported by NSERC Canada)
