Abstract
It has been recognized that newborn and fetal mammals exhibit greater resistance to the effects of anoxia than adults. This has been attributed to the prominence of glycolysis as an energy yielding pathway in early life. Since the efficiency of oxidative phosphorylation in the developing heart has not been assessed previously, the present investigation was undertaken. Heart mitochondria were isolated from the bovine fetus estimated by the crown-rump length and weight to range from 65 to 160 days gestational age. Mitochondrial efficiency was determined from ADP/O ratios and respiratory control values. Substrates entering the two flavoprotein limbs of the respiratory chain were utilized. ADP/O ratios obtained with glutamatemalate, a DPNH linked substrate, were above two in all and approached 3 in the five animals in the younger (65 to 80 day) group. With succinate as the substrate values were above one with many approaching two. Thus for both substrates ratios were in the normal adult range. All preparations exhibited respiratory control values considered normal for mitochondria isolated from the mature heart (average ratios above 6). Specimens oxidized the substrates readily with no apparent age relationship. Under the conditions of the isolation procedure employed, mitochondrial yields from the fetal hearts were generally half of those from the adult tissue. These preliminary data indicate that the machinery of oxidative phosphorylation in the developing heart is intact and functionally similar to that of the adult. (Supported in part by Massachusetts Heart Association) (SPR)
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Warshaw, J., Haessler, H. 1 Demonstration of Coupled Oxidative Phosphorylation in the Fetal Heart. Pediatr Res 1, 200 (1967). https://doi.org/10.1203/00006450-196705000-00008
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DOI: https://doi.org/10.1203/00006450-196705000-00008