Serotonin and distribution of radiocarbon from D-[14C-U]-glucose in Schistosoma mansoni.

Following a 60 min in vitro incubation of Schistosoma mansoni with D-[14C-U]-glucose 76% of the radiocarbon was incorporated into metabolic end products and excreted back into the medium. In the presence of 5-HT uptake of glucose increased 61%; excreted end products accounted for 87% of the radiocarbon, indicating increased levels of energy utilization. Substantial amounts of radiolabelled carbon from D-[14C-U-]-glucose were incorporated into glycogen, lipids, amino acids and proteins, suggesting the utilization of glucose carbon in the biosynthetic processes of the parasite. Incorporation of glucose carbon was diminished in the presence of 5-HT, indicating the priority of energy generation over biosynthesis to meet the demands of increased muscular activity.