Myocardial Lactate Metabolism in Fetal and Newborn Lambs
| Autor: | Hennie Knoester, W. G. Zijlstra, Jaap R. G. Kuipers, Beatrijs Bartelds, Janny Takens, Gioia B. Smid, Gertie C. M. Beaufort-Krol, Hugo S. A. Heymans |
|---|---|
| Přispěvatelé: | Groningen University Institute for Drug Exploration (GUIDE), Cardiovascular Centre (CVC) |
| Rok vydání: | 1999 |
| Předmět: |
Aging
medicine.medical_specialty Carbohydrate metabolism OXIDATION OXYGEN chemistry.chemical_compound Fetus Lactate oxidation In vivo CARBOHYDRATE Physiology (medical) Internal medicine blood flow Animals Medicine Lactic Acid isotopes FATTY-ACID METABOLISM lactate Sheep BLOOD-FLOW Fatty acid metabolism ATP PRODUCTION business.industry Myocardium Fatty Acids CONSUMPTION Heart Arteries Metabolism MUSCLE Carbohydrate Fetal Blood Glucose Endocrinology Animals Newborn chemistry Circulatory system ADULT SHEEP Energy Metabolism Cardiology and Cardiovascular Medicine business metabolism Oxidation-Reduction |
| Zdroj: | Circulation, 99(14), 1892-1897. LIPPINCOTT WILLIAMS & WILKINS |
| ISSN: | 1524-4539 0009-7322 |
| DOI: | 10.1161/01.cir.99.14.1892 |
| Popis: | Background —Around birth, myocardial substrate supply changes from carbohydrates before birth to primarily fatty acids after birth. Parallel to these changes, the myocardium is expected to switch from the use of primarily lactate before birth to fatty acids thereafter. However, myocardial lactate uptake and oxidation around birth has not been measured in vivo. Methods and Results —We measured myocardial lactate uptake, oxidation, and release with infusion of [1- 13 C]lactate and myocardial flux of fatty acids and glucose in chronically instrumented fetal and newborn (1 to 15 days) lambs. Myocardial lactate oxidation was the same in newborn (81.7±14.7 μmol · min −1 · 100 g −1 , n=11) as in fetal lambs (60.7±26.7 μmol · min −1 · 100 g −1 , n=7). Lactate uptake was also the same in newborn as in fetal lambs. Lactate uptake was higher than lactate flux, indicating lactate release simultaneously with uptake. In the newborn lambs, lactate uptake declined with age. Lactate uptake was strongly related to lactate supply, whereas lactate oxidation was not. The supply of fatty acids or glucose did not interfere with lactate uptake, but the flux of fatty acids was inversely related to lactate oxidation. Conclusions —We show that lactate is an important energy source for the myocardium before birth as well as in the first 2 weeks after birth in lambs. We also show that there is release of lactate by the myocardium simultaneously with uptake of lactate. Furthermore, we show that lactate oxidation may be attenuated by fatty acids but not by glucose, probably at the level of pyruvate dehydrogenase. |
| Databáze: | OpenAIRE |
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