Abstract
Recent studies of fetal sheep metabolism in unstressed preparations have suggested that amino acids (AA) may furnish up to 25% of the substrate for fetal aerobic metabolism after 125 days gestational age (GA). This investigation was performed to determine throughout gestation the activities in fetal sheep liver and kidney of key enzymes for gluconeogenesis. Tissue specimens from 10 fetuses of well-nourished ewes at 44-145 d. GA were assayed by spectrophotometric methods. Results: (1) After 125 d. GA substantial activities were found in both liver and kidney for glucose-6-p'tase (G6P), fructose-1,6-dipTtase (F1,6DP), pyruvate carboxylase, PEP carboxykinase, aspartate aminotransferase (asp AT), and alanine aminotransferase (ala AT). The activity in kidney for each enzyme except asp AT was comparable to or greater than the activity in liver.(2) Activities of 2 enzymes increased with gestation:
Conclusion: Significant activities of these enzymes in late gestation support the theories of fetal utilization of AA (a) as substrate for aerobic metabolism, and (b) for gluconeogenesis. Speculations: (1) Increasing capability for gluconeogenesis may occur as gestation proceeds. (2) The role of the kidney in overall fetal metabolism may be substantial.
(* μM Pi produced/min/g. protein; x ± SEM)
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Stevenson, R., Adcock, E., Morriss, F. et al. GLUCONEOGENIC ENZYMES IN FETAL SHEEP LIVER AND KIDNEY. Pediatr Res 8, 360 (1974). https://doi.org/10.1203/00006450-197404000-00122
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DOI: https://doi.org/10.1203/00006450-197404000-00122