Abstract
The present study compares the rates of Ca2+ uptake and Cd2+ accumulation in tilapia (Oreochromis mossambicus) between larvae preexposed to Cd2+ and naive larvae. Preexposure to Cd2+ induces some form of adaptation that attenuates the effects of Cd2+ later on. Exposure to Cd2+ decreased the uptake of Ca2+ but did not suppress the accumulation rate of Cd2+. A 12-fold increase in 96-h half-maximal lethal concentration was found in tilapia larvae preexposed to 0.45 μM Cd2+ from hatching for 3 days in comparison with naive 3-day-old larvae. The effects of Cd2+ on Ca2+ influx kinetics in larvae preexposed to 0.18 μM Cd2+ for 3 days were examined. The Michaelis constant for Ca2+ in the 0.18 μM Cd2+ preexposed larvae did not change significantly in the presence of Cd2+, whereas maximal velocity increased by ~23%. An enhanced Ca2+ uptake efficiency (~18%) was found in these Cd2+-acclimated larvae. The criterion that determines the survival of tilapia larvae encountering Cd2+ challenge is the degree of interference with Ca2+ homeostasis instead of the absolute amount of Cd2+ accumulated.
Original language | English (US) |
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Pages (from-to) | R1570-R1577 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 274 |
Issue number | 6 43-6 |
DOIs | |
State | Published - 1998 |
Keywords
- Acclimation
- Cadmium accumulation
- Calcium influx
- Half-maximal lethal concentration
- Maximum velocity
- Michaelis constant
ASJC Scopus subject areas
- Physiology
- Physiology (medical)