Oxygen uptake by dogfish gill tissue after several in vitro zinc treatments

Oxygen consumption by dogfish gill tissue is measured after several in vitro zinc treatments ranging from low contamination (0.2 ppm) to the 50% lethal concentration at 24 hours (180 ppm). Zinc inhibits respiration from 15 ppm and the inhibition increases along with greater zinc concentrations from 15 to 60 ppm. Thereafter the respiration level becomes stabilized with no further inhibition increases. A similar pattern is described with homogenates but inhibition is stronger and faster, while respiration does not stabilize. The results are discussed in relation to the possible role of the membrane and the toxicological effects caused by zinc.