The Journal of the Japanese Respiratory Society ONLINE JOURNAL
ABSTRACT
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Article in Japanese
Original Article
Acute Effect of 7% CO2 Breathing on Lactate, Pyruvate and Ketone Body Metabolism in Healthy Subjects
Sim Jae Joon
Second Department of Internal Medicine Toho University School of Medicine, 6-11-1 Omori-nishi, Ota-ku, Tokyo 143-8541
ABSTRACT
Although the effect of hypoxia on the tissue metabolism is well discussed, little is known about hypercapnia. To investigate the effect of hypercapnia on metabolism, we studied10normal subjects in a condition of acute normoxic hypercapnia, while they breathed a mixture of gases: 7% CO2, 21% O2 and the remainder, N2. Lactate, pyruvate, nonesterified fatty acid (NEFA), and ketone bodies were measured by taking blood samples before the study (C), when end tidal CO2 reached its peak level (P), and when end tidal CO2 returned to normal (R).Pyruvate decreased from0.66± 0.17mg/dl from (C) to (P), and reached its lowest value in (R). A significant decrement was found in (R) compared with (P) (p<0.05). Lactate increased gradually, but not significantly, from (C) to (R), while the lactate/pyruvate ratio increased significantly from (P) to (R). No significant change was found in the acetoacetate/3-hydroxybutylate ratio. These results suggest that acute hypercapnia may affect the metabolism via the mitochondria, and we conclude that hypercapnia may play an important role in the disruption of tissue metabolism in man.
KEYWORDS: Healthy subjects, Breathing of7% CO2, Lactate, Pyruvate, Keton body ratio, KBR
RECEIVED: 2000.2.8
JJRS, 39(5): 309-315, 2001
