Ontogenetic
Development of Energy-Supplying Enzymes
in Rat and Guinea-Pig Heart
A. BASS1, M. STEJSKALOVÁ2, A. STIEGLEROVÁ1, B. OÁDAL1,
M. AMÁNEK2
1Institute
of Physiology, Academy of Sciences of the Czech
Republic, 2Kardiocentrum,
University Hospital Motol, Prague, Czech Republic
Received
December 1, 2000
Accepted January 3, 2001
Summary
The
purpose of the present study was to compare the
ontogenetic development of the activity of
myocardial energy-supplying enzymes in two
mammalian species, differing significantly in
their level of maturation at birth. The animals
were investigated during the late prenatal period
and 2, 7, 14, 21, 25, 30, 63, 120 and 730 days
after birth in the rat and 2, 21, 84 and 175 days
in the guinea-pig. The following enzymes were
assayed in the right and left ventricular
myocardium: lactate dehydrogenase (LDH, lactate
uptake and/or formation), triose phosphate
dehydrogenase (TPDH, carbohydrate metabolism),
glycerol phosphate dehydrogenase (GPDH,
glycerol-P shuttle)), hexokinase (HK, glucose
phosphorylation), malate dehydrogenase (MDH,
tricarboxylic cycle), citrate synthase (CS,
tricarboxylic cycle) and hydroxyacyl-CoA
dehydrogenase (HOADH, fatty acid breakdown). The
rat heart, highly immature at birth, exhibits
three different developmental patterns of
energy-supplying enzymes, identical in both
ventricles: (i) two mitochondrial enzymes of
aerobic metabolism (CS, HOADH) and GPDH have a
relatively low activity at the end of prenatal
life; thereafter their activity steadily
increases, approaching the adult levels between
the 3rd and 4th postnatal weeks. A significant
decrease was observed between the 4th and 24th
months. (ii) MDH and LDH: prenatal values were
significantly higher as compared with the 2nd
postnatal day; after this period the activities
increased up to adulthood (4 months) and
decreased during senescence. (iii) The activities
of HK and TPDH are characterized by only moderate
changes during development. HK differs from all
other enzymes by the highest prenatal values,
which exceed even adult values. In contradiction
to the rat heart, the developmental differences
in more mature guinea-pig heart were
significantly less pronounced. The only
ontogenetic differences observed were the lower
activities of enzymes connected with aerobic
metabolism at the end of the prenatal period. Our
results point to possible differences in the
development of adaptive metabolic pathways in
animals with different levels of maturation at
birth.
Key
words
Heart
ˇ Ontogenetic development ˇ Energy metabolism
ˇ Rat ˇ Guinea-pig
Reprint
requests
Prof.
Dr. B. Oádal, Institute of Physiology,
Academy of Sciences of the Czech Republic,
Vídeňská 1083, 142 20 Prague 4, Czech
Republic, fax: 420 2 475 2125, e-mail: ostadal@biomed.cas.cz
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