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Metabolic fate of lactate after anoxia at 20°C in the Western painted turtle
Author(s) -
Hill Craig A.,
Puchowicz Michelle A.,
Brunengraber Henri,
Berger Richard,
Yarasheski Kevin E.,
Warren Daniel E.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.714.14
Subject(s) - glycogen , painted turtle , chemistry , metabolism , turtle (robot) , biochemistry , environmental chemistry , biology , ecology
Western painted turtles ( Chrysemys picta bellii ) can survive anoxia for 120 days at 3°C and tolerate plasma lactate concentrations approaching 200 mM. The metabolic fate of lactate accumulated over 6 hours of anoxia and 39 hours of recovery at 20°C was investigated with stable isotope tracer methodology. A bolus infusion of [U ‐ 13 C] ‐ lactate tracer was given via an intra‐arterial catheter 2 hours into anoxia. 13 C enrichment of metabolites and CO 2 from expired air, blood and bone were measured using gas chromatography and isotope ratio mass spectrometry. The tracer completely equilibrated with the lactate pool by the end of anoxia. M3‐glucose enrichment slowly increased throughout the recovery period, and liver glycogen accounted for 26–33% of the label at the end of recovery. CO 2 was the fate for ~44% of the lactate carbon, and CO 2 exchange with the bone accounted for ~18% of the label, indicating that the shell is an important sink for metabolically produced CO 2 . The plasma concentration and enrichment of beta‐hydroxybutyrate also increased. Our results demonstrate that painted turtles are more like mammals in that oxidation accounts for the largest fraction of the labeled carbon. Turtles primarily utilize some other substrate to replenish muscle glycogen stores, most likely glucose derived from liver. This research was funded by Saint Louis University and the National Institutes of Health .