High hydrostatic pressure (101 ATA) changes the metabolic design of yellowfreshwater eel muscle

The glycolytic pathway has been studied in the white muscle of yellow fresh water eel (Anguilla anguilla L.) exposed to high hydrostatic pressure (101 ATA) for 1 month. Using appropriate substrates and auxiliary enzymes to dri ve the flux towards glycerol phosphate, fluxes of glucose (J(A) then of glu cose 6-phosphate (J(B),) have been measured. The maximum acceleration durin g the transition from J(A) to J(B) was measured as the response time, t(m); the metabolic reprise, which gives information about the rapidity of a giv en metabolic change, was calculated as rho = (J(B)/J(A))t(m), i.e the ratio of the fluxes over the response time. An estimation in vivo has been perfo rmed for each parameter. Acclimatization to high pressure induces a signifi cant increase in the fluxes (P < 0.05), but the ratio J(B)/J(A) remains con stant. As the metabolic response time t(m) decreases, there is a significan t increase in the metabolic reprise rho (+ 60%, P < 0.01) which means that muscle from acclimatized fish has the capacity to increase the glycolytic f lux 1.6-times more than control fish muscle. These modifications in the met abolic design in pressure acclimatized fish are discussed and the hypothesi s is raised that pressure may optimize energy production to prepare eel phy siology to the new environment encountered during migration from freshwater to seawater and thus to a new type of energy demand. (C) 1998 Published by Elsevier Science Inc. All rights reserved.