In vitro estimation of the rate of hexose phosphorylation, by sequential pulsing with [3H]- and...

The rate of phosphorylation of 2-deoxy-D-glucose (2dGlc) was determined by incubating Schistosoma mansoni in vitro in [3H]2-deoxy-D-glucose; 60 sec after exposure to the [3H]dGlc, [14C]dGlc was added to the medium, and metabolic activity was arrested at 2 min by immersion of the tissue in ice-cold silicone oil. Column chromatographic separation of the neutral [3H]- and [14C]dGlc from the [3H]- and [14C]2-deoxy-D-glucose-6-phosphate permitted estimation of the quantity of [3H]dGlc phosphorylated in 2 min, and the proportion of [14C]dGlc phosphorylated in 1 min; thus a phosphorylation rate was determined from a single tissue sample. In male schistosomes derived from mouse infections 4.4 +/- 0.8% of the dGlc was phosphorylated each minute, and 4.2 +/- 0.9% in the females. Lower rates of phosphorylation were measured in schistosomes taken from hamsters where males phosphorylated 2.4 +/- 1.1% of the dGlc each minute, and in females 2.7 +/- 1.0%. These studies suggest the high rate of hexose utilization by schistosomes compares to the conscious rat brain, where 11% of the dGlc is phosphorylated each minute.