Accession Number : ADA308618

Title :   Biochemical Indices of High Pressure Tolerance in Marine Mammals.

Descriptive Note : Final rept. Apr 93-Nov 95,

Corporate Author : ALASKA UNIV FAIRBANKS INST OF MARINE SCIENCE

Personal Author(s) : Castellini, Michael A.

PDF Url : ADA308618

Report Date : 13 MAY 1996

Pagination or Media Count : 6

Abstract : The metabolic effects associated with the dramatic and repeated hydrostatic pressure changes faced by marine mammals are unknown. By measuring glucose utilization and lactate production, the effect of 2000 psi of pressure on glycolysis in red blood cells was compared among marine and terrestrial mammals. The effect of pressure on the kinetics of lactate dehydrogenase in cardiac tissue of marine and terrestrial mammals was also evaluated. Pressure affected LDH kinetics similarly in both groups, causing no change in Vmax or Km for pyruvate or NAD+, a decrease in lactate Km and n increase in NADH Km. At pressure, marine mammal RBCs generally had little change in glucose utilization rates relative to terrestrial mammals, in which the rate decreased. Lactate production rate was enhanced in some marine mammals, remained relatively unchanged in others and generally decreased in terrestrial mammals. lactate/glucose was well below the theoretical value of 2.0 except for dolphins and humans. In most cases,lactate/glucose shifted to higher values under pressure, suggesting a shift in metabolic pathway toward glycolysis. The effect of pressure on glycolysis is apparently complex, involving individual enzymes, possibly a shift in metabolic pathway and possibly glucose transport.

Descriptors :   *HUMANS, *HIGH PRESSURE, *METABOLISM, *TOLERANCES(PHYSIOLOGY), *DOLPHINS(MAMMALS), *BLOOD CELLS, TISSUES(BIOLOGY), HIGH RATE, PRODUCTION, MAMMALS, BIOCHEMISTRY, ENZYMES, RED(COLOR), RATES, TRANSPORT, PRESSURE, KINETICS, EARTH(PLANET), UTILIZATION, PRODUCTION RATE, HEART, BLOOD, GLUCOSE, AQUATIC ANIMALS, LACTATES, HYDROSTATIC PRESSURE, GLYCOLYSIS, LACTIC DEHYDROGENASE.

Subject Categories : Medicine and Medical Research
      Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE