In vivo -studies on the function of hemoglobin in the larvae of Chironomus thummi (insecta, diptera)

1. 1. The respiratory rate of the larvae of Chironomus thummi was monitored in a closed system. It was virtually constant until the pO 2 declined below 10 Torr. 2. 2. When hemoglobin was inhibited by CO the uptake of O 2 started decreasing already at 50 Torr. 3. 3. The function of hemoglobin was also studied by measuring the concentrations of metabolites in the larvae during recovery in hypoxie water (pO 2 = 15 Torr) after preceding anoxia (6hr). 4. 4. Normal levels of lactate, alanine, and malate were re-established within 3 hr. In the presence of CO this was markedly inhibited. 5. 5. Larvae immediately removed from their dwelling-tubes exhibited symptoms ofhypoxia in comparison with controls incubated for 3 hr in normoxic water without substrate.