The glucose uptake rate by plerocercoid of Diphyllobothrium sp. was a mean value of 5.35+/-0.80 micro-mole/hr/g of wet wt, and total CO(2) production rates by the plerocercoid larva averaged 7.54+/-0.73 micro-mole/hr/g of wet wt. The relative specific activity into respiratory CO(2) showed a mean value of 7.30 +/-0.90 per cent. The rate of CO(2) production derived from medium C(14)-glucose was a mean of 0.58+/-0.13 micro-mole/hr/g of wet wt. Therefore, the average value of 1.92+/-0.38 per cent of glucose utilized by the larvae from the medium C(14)-glucose was oxidized to respiratory CO(2). The tissue concentration of glycogen in plerocercoid larva was a mean of 46.28 +/-2.23 mg/g or 4.63+/-0.22 per cent/g of wet wt., and the turnover rate of glycogen pool was a mean of 0.049 +/- 0.012 %/hr or 0.010 +/- 0.003 mg/hr/g of wet wt. The average value of 2.76+/-1.00 per cent of glucose utilized by the larvae from the medium C(14)-glucose was incorporated to the glycogen. These data accounts for that only 5 per cent of the utilized glucose by the plerocercoid larvae participated in furnishing the oxidation into respiratory CO(2) and the synthetic process into glycogen.
