Isolated, intact hearts from foetal mice of 14 to 21 days' gestational age survive and beat in organ culture for several days when the sole external substrate available for energy production is pyruvate, acetoacetate, β-hydroxybutyrate, octanoate, or glucose. Survival with glucose is significantly longer than with the other substrates. Inhibition of oxidative phosphorylation or of glycolysis causes early death of the hearts. Utilization of glucose is greater in hearts of younger (14 to 17 day) foetuses than in those of older foetuses near term (> 19 days' gestation). Release of lactate is also greater in younger foetuses, both in absolute terms and as a proportion of the glucose consumed. The results suggest that long-term function in vitro of intact hearts of late-foetal mice requires the utilization of glucose as well as the oxidation of substrates through the tricarboxylic acid cycle. Glycolytic capacity assumes relatively less importance in cardiac metabolism as the foetus approaches term, but the availability of glucose remains essential for prolonged function.
ASJC Scopus subject areas
- Molecular Biology
- Cardiology and Cardiovascular Medicine