Volume 50: 237-245, 2001

Ontogenetic Development of Energy-Supplying Enzymes
in Rat and Guinea-Pig Heart

A. BASS1, M. STEJSKALOVÁ2, A. STIEGLEROVÁ1, B. OŠÁDAL1,
M. ŠAMÁNEK
2

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. Ošádal, 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

PHYSIOLOGICAL RESEARCH
Š 2001 by the Institute of Physiology, Czech Academy of Sciences

ISSN 0862 - 8408

Issue 3