Profiles of Substrate Levels of the Central Metabolic
Pathways in Frog Heart
P. AREsE, A. BasTA, and L. ROSSINI
With 3 Figures
Abstract
Stepwise discriminant analysis (according to DIXON'S BMDX 67 jBMD 07M
program) allows highly significant discrimination between groups of mutually
correlated little-differing metabolic parameters. The analysis was applied to groups
of 18 and 35 parameters (18 glycolytic-, citric-acid-cycle-, high-energy-compounds
plus 17 derived values, such as in vivo equilibrium constants, redox ratios, etc.)
determined in frog heart. The following conditions were chosen: wash-out
effects, and short-term effects of ionic ally modified Ringer-solutions and of ouabain.
The first purpose of this communication is to investigate how functionally comparable dynamic situations correlate with the behavior of the
glycolytic-, citric-acid-cycle- and energy-rich-substrates. The second aim
is to describe further patterns of metabolite movements in complex cellular
systems changing from one steady-state to another, in order to make the
formulation of computer models [7, 8] more general and realistic. Frog
myocardium was chosen because of its homogeneity-owing to its lack of
connective tissue and coronary circulation-and because of its great ionic
mobility [3]. Injection with calcium-enriched or ouabain-containing Ringer
solutions had no effect on heart dynamics after 30 sec, caused a moderate
positive inotropism after 60 sec, and a sustained contracture after 120 sec.
At these times, the hearts were quick-frozen and 18 substrates were measured. Owing to the great number of parameters, computer-assisted
stepwise discriminant analysis was necessary. The analysis was performed
separately on the 18 substrates, 17 derived values or on the resulting sum
of parameters. The discriminating differences between normal and treated
hearts were significant at the 0.01 F level. The statistical procedure we
adopted identified little-differing but functionally relevant parameters, and
changes of the whole pattern.
Materials and Methods
Frogs of both sexes, weighing 15 to 30 g were used. Control animals were
injected in the vena cava inferior with Ringer-frog solution. Treated frogs were
injected with ionically modified (4 X Ca++, minus K +) or ouabain-containing (0.1 %)
Pathways in Frog Heart
P. AREsE, A. BasTA, and L. ROSSINI
With 3 Figures
Abstract
Stepwise discriminant analysis (according to DIXON'S BMDX 67 jBMD 07M
program) allows highly significant discrimination between groups of mutually
correlated little-differing metabolic parameters. The analysis was applied to groups
of 18 and 35 parameters (18 glycolytic-, citric-acid-cycle-, high-energy-compounds
plus 17 derived values, such as in vivo equilibrium constants, redox ratios, etc.)
determined in frog heart. The following conditions were chosen: wash-out
effects, and short-term effects of ionic ally modified Ringer-solutions and of ouabain.
The first purpose of this communication is to investigate how functionally comparable dynamic situations correlate with the behavior of the
glycolytic-, citric-acid-cycle- and energy-rich-substrates. The second aim
is to describe further patterns of metabolite movements in complex cellular
systems changing from one steady-state to another, in order to make the
formulation of computer models [7, 8] more general and realistic. Frog
myocardium was chosen because of its homogeneity-owing to its lack of
connective tissue and coronary circulation-and because of its great ionic
mobility [3]. Injection with calcium-enriched or ouabain-containing Ringer
solutions had no effect on heart dynamics after 30 sec, caused a moderate
positive inotropism after 60 sec, and a sustained contracture after 120 sec.
At these times, the hearts were quick-frozen and 18 substrates were measured. Owing to the great number of parameters, computer-assisted
stepwise discriminant analysis was necessary. The analysis was performed
separately on the 18 substrates, 17 derived values or on the resulting sum
of parameters. The discriminating differences between normal and treated
hearts were significant at the 0.01 F level. The statistical procedure we
adopted identified little-differing but functionally relevant parameters, and
changes of the whole pattern.
Materials and Methods
Frogs of both sexes, weighing 15 to 30 g were used. Control animals were
injected in the vena cava inferior with Ringer-frog solution. Treated frogs were
injected with ionically modified (4 X Ca++, minus K +) or ouabain-containing (0.1 %)