Glucose and oxygen metabolism in the fetal foal during late
gestation.
Fowden, Abigail L., and The Late Marian Silver.
Physiological Laboratory, Downing Street, Cambridge, CB2 3EG
APStracts 2:0194R, 1995.
Using U14C glucose tracer methodology, the rates of umbilical uptake,
utilization, oxidation and production of glucose were determined in 9
chronically catheterized fetal foals in the fed state between 268 and
325 days of gestation (term 335 days). At the same time, the rates of
umbilical O2 and lactate uptake were measured in all 9 fetuses by
Fick principle. The mean fetal rates of umbilical glucose uptake,
glucose utilization and CO2 production from glucose carbon were 36.9
+/- 2.5, 36.4 +/- 1.7 and 117.7 +/- 17.4 [mu]mol/min/kg fetal body
weight respectively (n=9). Endogenous glucose production was
therefore negligible in the fetal foal in the fed state. Production
of CO2 from glucose carbon accounted for 40.9 +/- 6.5% of the
umbilical O2 uptake which averaged 292 +/- 15 [mu]mol/min/kg (n=9).
No significant changes in fetal glucose or O2 metabolism were
observed with increasing gestational age. The rates of umbilical
glucose uptake, glucose utilization and CO2 production from glucose
carbon (P<0.01), but not the rate of umbilical O2 uptake
(P>0.05), were positively correlated with the fetal blood
glucose level. There was a significant umbilical lactate uptake in
the fetuses older than 290 days (12.3 +/- 4.1 [mu]mol/min/kg, n=5,
P<0.05) but not in the younger animals (6.2 +/- 9.6
[mu]mol/min/kg, n=4, P>0.05). Hence, glucose is used for both
oxidative and non-oxidative metabolism in utero and is a major,
although not the sole, oxidative substrate in the fetal foal during
late gestation.
Received 24 February 1995; accepted in final form 6 July 1995.
APS Manuscript Number R133-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 18 July 1995.