Membrane transport of inositol by Hymenolepis diminuta (Cestoda).
The absorption of myoinositol by Hymenolepis diminuta involved diffusion that occurred at all substrate concentrations tested; at low substrate concentrations the mediated component predominated. The mediated process exhibited saturation kinetics with a Vmax and Kt of 0.011 mumoles/g of the ethanol-extracted dry wt/4 min and 0.0067 mM, respectively. Myoinositol transport was sensitive to changes in temperature, pH, and sodium ion concentration. D-Glucose was a noncompetitive inhibitor of myoinositol transport, but myoinositol had no effect on D-glucose absorption. Phlorizin interacted competitively with the myoinositol transport system. Various sugar alcohols and amino acids had no effect on myoinositol transport. These results indicate that a separate transport system exists in H. diminuta for myoinositol.
D000042:Absorption; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D002241:Carbohydrates / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004058:Diffusion; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006926:Hymenolepis / Q000378:metabolism*; D007294:Inositol / Q000378:metabolism*; D007700:Kinetics; D010695:Phlorhizin / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013696:Temperature
D000596:Amino Acids; D002241:Carbohydrates; D007294:Inositol; D012964:Sodium; D010695:Phlorhizin; D005947:Glucose